bootstrap: implement test repo manifest generation

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Move RepoManifest to gbp

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
bootstrap: return to current branch

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
bootstrap: build without switching branches

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Add test repo manifest

For testing gbp pq-rpm, for now.

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>