Add async CRUD methods to IProjectClient

[belcher-rok]

• Adds async CRUD methods to IProjectClient.
• Improves the Mock ProjectClient to better emulate actual GitLab behavior:
  • Project Create must specify Name or Path.
  • Auto-generate missing Path from Name, and vice-versa.
  • Cannot create project with duplicate Name (case-sensitive).
  • Cannot create project with duplicate Path (case-INsensitive).
  • Project.BuildTimeout is in seconds, not minutes.
  • GitLab ignores ProjectCreate.DefaultBranch unless ProjectCreate.InitializeWithReadme is true.
  • Project.ToClientProject() did not populate NameWithNamspace.
  • Project.FullName contains spaces around the slash separator.
• Added tests to verify GitLab and Mock behaviors.

[belcher-rok]

@Toa741 Anything I can do to help move this along?

[Toa741]

@Toa741 Anything I can do to help move this along?

Hey John :), I was on vacation, everything looks good, just had one question regarding the Project init in the mock