Upgrade trusted app relationships

We need to understand how they currently work - speak to Erik and Felix

Discussion outcomes:

• The fisheye instances are assumed to be using trusted apps if there are no username/password credentials set.
• This works in two circumstances:
  1. The fisheye server is anonymously accessible, so no username/password is needed. Fisheye server ignores the trusted apps headers.
  2. The fisheye server is configured with trusted apps for the jira instance. The trusted apps header is honoured.
• When upgraded to UAL, we can assume that any fisheye instance without authentication credentials are trusted apps applications, and setup a UAL link and set the outbound authentication to trusted apps. Then, this will work for both circumstances outlined above.