Ignore files in a cloned repository - patterns
Git will ignore automatically generated files. Ignored patterns can be
specified in config. Patterns are applied in '.git/info/exclude' file only
when a repository is cloned. And changes are valid only for a local
repository.
Functionality is implemented in rpkg. This commit includes only patterns.
Relates: COMPOSE-2794
Signed-off-by: Ondrej Nosek <onosek@redhat.com>