Mirrors: Create mirrors for projects with git remote URL.

Create local git mirrors for projects with a remote URL.
This is to be used for extracting more details about specific commits,
and for managing release history.
AutoFixture: Use AutoFixture with AutoMoq.

Add reference to AutoFixture and create base test classes
for use in unit tests and integration tests.
Use Moq for mocking dependencies for AutoFixture.
Use autofixture for unit tests of the command bus.
Mirrors: Test git mirrors command handler.