* ReposOwner view
shows all repos owned by a person or organization
uses /:repoOwner urls (e. g. ci.example.org/example-org)
also includes a link from the repo page to the owner page
related to #468
* ReposOwner remove add btn; msg if no projects; grid
implements the changes suggested by @anbraten:
- removed the `add repository` button
- now shows a message `This organization / user does not have any projects yet.`
when appropriate
now uses `grid` instead of `flex` on desktop to keep the search bar
centered and always in the same place