Add script to fix which schools are attributed to BLMK and N&W

These SAIS teams are currently configured with all teams in their area 
wheareas they should be configured with only a limited selection of schools. 
This change amends them to have only and exactly the schools that they should 
have.

Jira-Issue: MAV-2352
Jira-Issue: MAV-2353

Author: MartinVanIJcken