1077506 - [RFE] Support to list details information about one specific pulp repo

https://bugzilla.redhat.com/show_bug.cgi?id=1077506
Now it is possible list information about specific repo in details, summary and specifying different fields.

This commit also contains:
- pep8
- docs
query_parameters are needed, because if i will specify --details option it will contain the distributors and importers boolean value i.e. ({'importers': True, 'distributors': True})
`pulp-admin repo list --repo-id xxx --details`