Plugins list: add plugin maintainers to generated plugin list

This helps users to find plugin maintainers.

Basic authentication credentials of a user having read access to the
plugins owner group information can be passed via environment variables
"user" and "password" otherwise the user is prompted for the missing
credentials.

Bug: Issue 11640
Change-Id: Ib2a3e6515133b65063c4cd6102b3fdf0252da00a
2 files changed