feat(repository): use git bundles in runners + refactor credentials

[corrieriluca]

This PR include changes from the following PRs:

• feat(runner): launch runners on specific commits #529
• refactor(provider): create dedicated credentials package and rework repository provider #528

And the following additional changes that merges the two:

• Make repository controller use the GetChanges function from GitProvider to set LastRelevantCommit annotation on TerraformLayers
• Test everything altogether
• Write unit tests:
  • Webhook should annotate repositories on push events
  • RepositoryController should annotate layers when new revision is available
• Enable by default the repository controller in Burrito's default config
• Add documentation on migration to repository credentials
• Add documentation on Git bundles and repository controller mechanics

List of tests implemented on the TerraformRepository controller

All tests pass and check if:

• the TerraformRepository ends in the correct state
• updates a git bundle to the datastore
• annotates correctly the TerraformLayers it manages to trigger reconciliation on the TerraformLayer side (especially with the LastRelevantCommit annotation which is now required by the Layer controller to perform any action).

Nominal cases:

• When a TerraformRepository without TerraformLayer is created
• When a TerraformRepository has not TerraformLayers anymore
• When a TerraformRepository with one TerraformLayer is created
• When a TerraformRepository with multiple TerraformLayer is created
• When a TerraformRepository has not been synced in the last 24h and changes are detected for some layers
• When a new TerraformLayer is created for a existent TerraformRepository
• When a TerraformRepository is already synced recently
• When a TerraformRepository has not been synced in the last 24h but is already on last revision
• When a TerraformRepository has a recent Sync Now annotation for a branch
• When a TerraformRepository has an OLD Sync Now annotation for a branch

Error cases:

• When the Git Providers fails for a newly created TerraformRepository
• When the last sync of the TerraformRepository has already failed

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 28.01519% with 758 lines in your changes missing coverage. Please review.

Project coverage is 40.07%. Comparing base (ce980e1) to head (301ca65).

Files with missing lines	Patch %	Lines
internal/repository/providers/github/github.go	6.47%	129 Missing and 1 partial ⚠️
...ternal/repository/providers/standard/repository.go	0.00%	123 Missing ⚠️
internal/repository/providers/gitlab/gitlab.go	14.47%	64 Missing and 1 partial ⚠️
internal/repository/providers/mock/mock.go	0.00%	57 Missing ⚠️
internal/repository/providers/gitlab/api.go	0.00%	44 Missing ⚠️
internal/repository/credentials/credentials.go	66.40%	31 Missing and 11 partials ⚠️
internal/repository/providers/github/api.go	0.00%	41 Missing ⚠️
internal/datastore/client/client.go	0.00%	38 Missing ⚠️
internal/repository/repository.go	0.00%	37 Missing ⚠️
internal/datastore/client/mock.go	0.00%	35 Missing ⚠️
... and 15 more

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #605      +/-   ##
==========================================
+ Coverage   37.33%   40.07%   +2.74%     
==========================================
  Files          81       86       +5     
  Lines        5874     5771     -103     
==========================================
+ Hits         2193     2313     +120     
+ Misses       3522     3275     -247     
- Partials      159      183      +24     

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[corrieriluca]

Documentation is now up-to-date with changes in the PR