Look for *all* Person names, and futher Positions

Also remove redundant .all()s before .filter()s.
Also look for member <-> provincial-legislature
Remove trailing space from a couple of names
Small corrections to names to help parsing
Store multiple Person objects per name form

Also include name forms where you just take the first and last name,
since some legal_name entries have many middle names.
Phone numbers can contain NO-BREAK SPACE or / characters
Remove an unused variable
Remove dots after initials, curly quotes and add a semi-colon separator
Correct a couple of names in the constituency office data
Improve an error message
Remove references to PCOs
Remove an unused parameter from find_pombola_person
Also look for positions titled "Member of the Provincial Legislature"
Look for any MP, not just currently active ones

This is because some constituency contacts seem to be ex-MPs, going
by the start and end dates.
Now we have longer party names, we have to extract their abbreviations

The abbreviation is more appropriate for using in slugs and identifiers,
for example.
Correct a mispelling now fixed in the source data
Look for legacy forms of slugs as well

On the initial import, there was some confusion about the terminology
of constituency "office" vs "area", so there are entries in the
database with slugs containing the wrong term - we need to be able
to find these anyway, so look for a variety of forms of the slug.
Add a note about a drawback of the name resolution
ZA constituency data import: Update the introductory comments