The initial version of these migrations were defined too broadly. Since they
only matched on KBO numbers they also included the KBO organisations, imported
from wegwijs, adding them as participants.
This commit adds extra checks to exclude KBO organisations from being added as a
participant for a public OCMW association. Furthermore, the main migration is
split into two parts to work around an error otherwise encountered when
executing the migration as a single whole.
660c9b6848