Rename Mirror to Repository

Rename Mirror and related classes to Repository. This change
better reflects what the classes are about. The old name was just to
confusing.

Signed-off-by: Christoph Kassen <c.kassen@telekom.de>
Rename Mirror to Repository (part 2)

Rename Mirror and related classes to Repository. This change
better reflects what the classes are about. The old name was just to
confusing.

This includes renaming tests, local variables and comments.

Signed-off-by: Christoph Kassen <c.kassen@telekom.de>
Merge pull request #33 from TelekomCloud/feature/mirror_rename

Rename Mirror to Repository