PQIR states in the categorisation page

**User story**
As a user I want the state of PQIR's to be visible so that I can filter PQIR's not in use, solved etc.

**Additional info**
Originates from #165.
Relates to #204 , #205, #346

**User input**
When a problem is deleted from a flow, it still is registered as an "existing problem" and still appears in "categorize PQIR's"
Example: Flow #33 and P18

**User**
SM

**Sharepoint ID**
105

Start at the categorisation page and reproduce the reported case with Flow #33 and P18. Trace how a problem deleted from a flow remains an existing problem, then verify that PQIR states are visible and filterable and that deleted problems no longer appear.

Written by the indexing model from the issue text.