shadow: Fix an error in the regex to detect shadow repository URLs.

tests: Add some tests to check that events/extensions are triggered on hook execution. This also includes tests to check that events/extensions are NOT triggered on requests to shadow repositories.

tests: Add new attribute `is_shadow_repo` to test dummy extra data.

tests: Add shadow clone url to expected api return value.

tests: Add missing key/value to vcs operation dummy dict.

lib: Fix missing space char in bad slug characters string.

vcs: Explicit use one of the repo names (acl, url, vcs)

vcs: Clean up the shadow-repo-expose code and make some nicer comments.

vcs: Move logging from vcs to simplevcs

vcs: Move shadow repo regex up to class level.