LogData also contains a new LogMetadata struct

Also rename to Metadata

What
---
Make the retryableHTTP client introduced in
https://gitlab.com/gitlab-org/gitlab-shell/-/merge_requests/703 the
default HTTP client.

Why
---
In
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979#note_1254964426
we've seen a 99% error reduction on `git` commands from `gitlab-shell`
when the retryableHTTP client is used.

This has been running in production for over 2 weeks in `us-east1-b` and
5 days fleet-wide so we should be confident that this client works as
expected.

Reference: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979


Signed-off-by: Steve Azzopardi <sazzopardi@gitlab.com>

What
---
- Update the `client.HttpClient` fields to have `http.Client` and
  `retryablehttp.Client`, one of them will be `nil` depending on the
  feature flag toggle.
- Create new method `newRetryableRequest` which will create a
  `retryablehttp.Request` and use that if the
  `FF_GITLAB_SHELL_RETRYABLE_HTTP` feature flag is turned on.
- Add checks for `FF_GITLAB_SHELL_RETRYABLE_HTTP` everywhere we use the
  http client to use the `retryablehttp.Client` or the default
  `http.Client`
- New job `tests-integration-retryableHttp` to run the integraiton tests
  with the new retryablehttp client. We didn't update go tests because
  some assertions are different and will break table driven tests.

Why
---
As discussed in
https://gitlab.com/gitlab-org/gitlab-shell/-/merge_requests/703#note_1229645097
we want to put the client behind a feature flag, not just the retry
logic. This does bring extra risk for accessing a `nil` field but there
should be checks everytime we access `RetryableHTTP` and `HTTPClient`.

Reference: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979


Signed-off-by: Steve Azzopardi <sazzopardi@gitlab.com>

What
---
Change the default `HTTP.Client` to
`github.com/hashicorp/go-retryablehttp.Client` to get automatic retries
and exponential backoff.

We retry the request 2 times resulting in 3 attempts of sending the
request, the min retry wait is 1 second, and the maximum is 15
seconds.

Hide the retry logic behind a temporary feature flag
`FF_GITLAB_SHELL_RETRYABLE_HTTP` to easily roll this out in GitLab.com.
When we verify that this works as expected we will remove
`FF_GITLAB_SHELL_RETRYABLE_HTTP` and have the retry logic as the default
logic.

Why
---
In https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979 users
end up seeing the following errors when trying to `git-clone(1)` a
repository locally on in CI.

```shell
remote: ===============================
remote:
remote: ERROR: Internal API unreachable
remote:
remote: ================================
```

When we look at the application logs we see the following error:

```json
{ "err": "http://gitlab-webservice-git.gitlab.svc:8181/api/v4/internal/allowed":
dial tcp 10.69.184.120:8181: connect: connection refused", "msg":
"Internal API unreachable"}
```

In
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979#note_1222670120
we've correlated these `connection refused` errors with infrastructure
events that remove the git pods that are hosting
`gitlab-webservice-git` service. We could try to make the underlying
infrastructure more reactive to these changes as suggested in
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979#note_1225164944
but we can still end up serving bad requests.

Implementing retry logic for 5xx or other errors would allow users to
still be able to `git-clone(1)` reposirories, although it being slower.
This is espically important during CI runs so users don't have to retry
jobs themselves.

Reference: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/7979
Closes: https://gitlab.com/gitlab-org/gitlab-shell/-/issues/604


Signed-off-by: Steve Azzopardi <sazzopardi@gitlab.com>

While gitlab-shell currently has a major version of v14, the module path
it exposes is not using that major version like it is required by the Go
standard. This makes it impossible for dependents to import gitlab-shell
as a dependency without using a commit as version.

Fix this by changing the module path of gitlab-shell to instead be
`gitlab.com/gitlab-org/gitlab-shell/v14` and adjust all imports
accordingly.

Changelog: fixed

In this case we don't need to propagate cleanup
function. It simplifies the code.

Previously, gitlab-shell did not pass a context through the application.
Correlation IDs were generated down the call stack instead of passed
around from the start execution.

This has several potential downsides:

1. It's easier for programming mistakes to be made in future that lead
to multiple correlation IDs being generated for a single request.
2. Correlation IDs cannot be passed in from upstream requests
3. Other advantages of context passing, such as distributed tracing is
not possible.

This commit changes the behavior:

1. Extract the correlation ID from the environment at the start of
the application.
2. If no correlation ID exists, generate a random one.
3. Pass the correlation ID to the GitLabNet API requests.

This change also enables other clients of GitLabNet (e.g. Gitaly) to
pass along the correlation ID in the internal API requests
(https://gitlab.com/gitlab-org/gitaly/-/issues/2725).

Fixes https://gitlab.com/gitlab-org/gitlab-shell/-/issues/474

Other functions are still expecting for `CommandArgs` instead
of `Shell`. They should be expecting `commandargs.Shell` now
since it has been renamed.

The reporter struct can be used for passing around and reporting to
the io.Writer of choice.

This allows gitlab-shell to be called with an argument of the format
`key-123` or `username-name`.

When called in this way, `gitlab-shell` will call the GitLab internal
API. If the API responds with user information, it will print a
welcome message including the username.

If the API responds with a successful but empty response, gitlab-shell
will print a welcome message for an anonymous user.

If the API response includes an error message in JSON, this message
will be printed to stderr.

If the API call fails, an error message including the status code will
be printed to stderr.