- Introduce lint and post-test stages
- Move all lint related jobs to the lint stage
- Move all post-test related jobs to the post-test stage

Signed-off-by: Rémy Coutable <remy@rymai.me>

We no longer need the workaround as the config file has been
renamed from `.erb` to `.tpl`.

Copies the `/etc/gitaly/config.toml.erb` file as
`/etc/gitaly/config.toml` file as the latest version of gitaly
CNG image no longer writes it but is required by Gitaly to run.

This job is added per the documentation:
https://docs.gitlab.com/ee/development/go_guide/#automatic-linting

Add libkrb5-dev to golangci-lint job

This is needed to process internal/sshd/gssapi.go.

Go v1.21 was just released today (https://go.dev/doc/go1.21), so let's
make sure our builds work with it.

All changes in our fork have been upstreamed in the latest `master` of
`golang.org/x/crypto`, so upgrade to that version. This version
requires Go 1.19 due to a new UNIX build constraint
(https://gitlab.com/gitlab-org/golang-crypto/-/merge_requests/13#note_1462100383).

Relates to https://gitlab.com/gitlab-org/gitlab-shell/-/issues/623

Changelog: changed

We want to use both go and ruby cache for test jobs since we run
go and rspec tests in that job.

We experienced a flaky failure of pipeline on `main` due to
caching changes.

To prevent that, we split the cache jobs specific to go and ruby
and use them accordingly. We also set the policy to `pull-push` on
specific jobs that need to update the cache.

We only use Ruby for running integration tests so we don't need
different versions of Ruby.