Extract GitAccessProject

What does this MR do?

Extract project access check out of GitAccess as GitAccessProject, containing project only operations, such as creating project during the push if project does not exist.

Part of #207871 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.