Create ResourceTree from Git

[Kaliumhexacyanoferrat]

As a developer, I would like to access resources hosted on a git repository within my project, so that I can serve content from there.

Example

var tree = ResourceTree.FromGit("https://my.repo", "v1.0.0")
                       .Refresh(PullPolicy.Always);

Host.Create()
    .Handler(DirectoryListing.From(tree))
    .Run();

Acceptance criteria

• The functionality is implemented in a new "GenHTTP.Modules.Git" module
• Repositories can be accessed using SSH or HTTPS
• Secured repositories can be specified
• The handler performs the initial checkout on PrepareAsync
• The repository is checked out into a local folder
• The repository is checked out shallow, if possible
• A checkout revision (hash, tag, branch) can be specified
• The local state is discarded on disposal