[Feature] Make it possible to run against a git repository and generate a unit test based on the git history

[arturcic]

Let's say we have a git repo, we run against it and we generate the

using var fixture = new EmptyRepositoryFixture();
fixture.Repository.MakeATaggedCommit("1.0.0");
fixture.Repository.CreateBranch("development");
Commands.Checkout(fixture.Repository, "development");

//Create an initial feature branch
var feature123 = fixture.Repository.CreateBranch("feature/JIRA-123");
Commands.Checkout(fixture.Repository, "feature/JIRA-123");
fixture.Repository.MakeCommits(1);

//Merge it
Commands.Checkout(fixture.Repository, "development");
fixture.Repository.Merge(feature123, Generate.SignatureNow());

//Create a second feature branch
fixture.Repository.CreateBranch("feature/JIRA-124");
Commands.Checkout(fixture.Repository, "feature/JIRA-124");
fixture.Repository.MakeCommits(1);