A number of APBs were accidentally `org:linkedTo` all municipalities in
municipality and an APB for which:
- the APB is linked to more than 1 municipality; and
- the municipality does not match that of the APB's primary site.
The first condition avoids we remove `org:linkedTo` triples for APBs that were
created by the users, as these are only linked with a single municipality.
Originally the starting dates for the new governing bodies for the new
legislature was set to `2025-01-01` for all relevant municipalities, OCMWs,
districts, and provinces.
These migrations change that to more correct starting dates:
* For organisations that are **not** involved in mergers the new starting data
is `2024-12-02`, the first day installation meetings are allowed[1].
* For organisations that are involved in mergers the new starting date is
`2025-01-01`, the first work day of the new year on which the mergers take
effect. Note: this migration assumes there are no other start dates on
`2025-01-01`, so the migrations have to be run in the specified order.
[1] https://www.vlaanderen.be/lokaal-bestuur/organisatie-en-werking/gemeenteraad/installatie
For each of the governing bodies created by the migrations in the previous
commit, now add the corresponding mandates and functions.
Within a organisation some governing bodies share the same mandates. For
example, for municipalities the governing body "Burgemeester" and "College van
burgemeester en schepen" both refer to the SAME instance of mandates for
"Burgemeester" and "Aangewezen burgemeester".
To achieve this the some migrations contain a second `INSERT` clause in which
the other governing body that contains the necessary mandates is selected to be
able to determine the correct mandate URI. This only works on two conditions:
1. Migrations that depend on each must be executed in the correct order. For
example, the migration inserting the mandates for "College van burgemeester
en schepen" must be executed after that for "Burgemeester". The former will
reuse mandates created by the latter.
2. The UUID for the shared mandates is calculated in exactly the same way in
migrations that depend on each other.
