Link to +edit or suggest contacting the owner instead of suggesting an email to feedback@ with bug tracker details

[Gavin Panella]

For example, on <https://bugs.launchpad.dev/thunderbird/+filebug>, the
following message appears:

  Launchpad doesn't know what bug tracker Mozilla Thunderbird uses. Do
  you know? Tell us about it.

Where "Tell us about it" is a link to <email address hidden>.

This is not a very good story for users; it's a dead-end to
most. Ideally we want to avoid showing this message altogether.

Instead, perhaps:

  * If the user can edit the project, he/she should be given a link to
    the +edit page, and brief instructions on what to do. Maybe even
    better would be to provide a form inline.

  * For users without edit permissions, there could be a link to
    <project owner>/+contactuser, with brief instructions on what to
    ask for. Again, it might be better with the +contactuser form
    inline, prefilled with a skeleton message.

  * For a project with no bug tracker specified (or explicitly set to
    none), we could temporarily give the user permission to set the
    bug tracker.

The first two ideas would be easy to implement in their simpler forms.