Sqservices 1533 be give saml id ps human readable names in tm

[battermann]

https://wearezeta.atlassian.net/browse/SQSERVICES-1533

handle is an optional query parameter on the POST and PUT requests. Can't easily add it to the body because the content-type is XML. Refactoring this will be a breaking change for the clients.

When a handle is not given, we will generate one like "IdP 1..n" and take the first one that is not used already.

If an IdP already exists, the handle that is returned is generated from the uuid of the IdP, taking the first 6 characters, e.g.

IdP 63621f

Since IdP handles are only alias, the uniqueness requirements for the handle can be a bit softer. Also, team admins can simply change the handles in case of a clash.

There was a discussion in the BE channel about a potential data migration. But the current implementation doesn’t need one, if it is acceptable from the user’s point of view to have the handles generated from the IdP Id as described above. There is also no need to update the database on GET requests, as discussed elsewhere.

Checklist

• The PR Title explains the impact of the change.
• The PR description provides context as to why the change should occur and what the code contributes to that effect. This could also be a link to a JIRA ticket or a Github issue, if there is one.
• If a cassandra schema migration has been added, I ran make git-add-cassandra-schema to update the cassandra schema documentation.
• changelog.d contains the following bits of information (details):
  • A file with the changelog entry in one or more suitable sub-sections. The sub-sections are marked by directories inside changelog.d.