feat: Add AzureDevops ScmProvider

[eegseth]

Adds Azure DevOps support as an SCM provider, with both PAT and Azure Workload Identity authentication methods.

Fixes #303

[codecov-commenter]

Codecov Report

❌ Patch coverage is 19.00826% with 490 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.06%. Comparing base (cc4a08d) to head (c6a606e).

Files with missing lines	Patch %	Lines
internal/scms/azuredevops/pullrequest.go	3.05%	286 Missing ⚠️
internal/scms/azuredevops/git_operations.go	41.77%	89 Missing and 3 partials ⚠️
internal/scms/azuredevops/commit_status.go	5.55%	85 Missing ⚠️
internal/utils/utils.go	10.00%	8 Missing and 1 partial ⚠️
internal/controller/commitstatus_controller.go	0.00%	7 Missing ⚠️
...ternal/controller/argocdcommitstatus_controller.go	0.00%	3 Missing ⚠️
...rnal/controller/changetransferpolicy_controller.go	0.00%	3 Missing ⚠️
internal/scms/azuredevops/token_manager.go	91.89%	2 Missing and 1 partial ⚠️
internal/controller/pullrequest_controller.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #557      +/-   ##
==========================================
- Coverage   50.90%   47.06%   -3.85%     
==========================================
  Files          35       39       +4     
  Lines        4186     4791     +605     
==========================================
+ Hits         2131     2255     +124     
- Misses       1801     2280     +479     
- Partials      254      256       +2     

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[crenshaw-dev]

Did a quick first pass, it's looking good!

[crenshaw-dev]

Apologies for the delayed review. There was something bothering me that I couldn't quite figure out, and I think I finally made sense of it.

All of the existing providers is accessible via one of two modes:

1. ClusterScmProvider: created by an admin along with creds, accessible to tenants in any namespace
2. ScmProvider: created by tenants in their own namespaces who must also provide their own credentials

This new provider breaks that binary. If I as a namespaced tenant can create an ScmProvider, I can take advantage of the creds (the workload identity) of the controller in the admin-controlled namespace.

I think that, for this PR, we should make Azure DevOps workload identity available only in ClusterScmProviders. In a follow up PR we can add workload identity support to ScmProviders in a way that requires the tenant to provide their own credentials.