Issue: GREG-89

To make handling info about roles and persons easier we split them into
separate objects. The Profile page has now gotten its own api endpoint
where a sponsor has access to all guests instead of only those they are
sponsor for which is used on the sponsor frontpage. This is necessary
since a sponsor may want to give a role to someone they are not
currently sponsor for.

Allows changes to start- and end date for guest roles. A new endpoint
has been added to the ui api for doing PATCH request to support this.
The max days of each role type is respected.

Resolves: GREG-83