Move MetaData into command package

internal/command/command.go

internal/command/command_test.go

internal/command/discover/discover.go

internal/command/discover/discover_test.go

internal/command/receivepack/receivepack.go

internal/command/receivepack/receivepack_test.go

internal/command/uploadarchive/uploadarchive.go

internal/command/uploadarchive/uploadarchive_test.go

internal/command/uploadpack/uploadpack.go

internal/command/uploadpack/uploadpack_test.go

internal/config/config.go

internal/config/config_test.go

internal/sshd/connection.go

internal/sshd/session.go

internal/sshd/sshd.go

internal/sshd/sshd_test.go