Define time period for a functionary position's door-access

The system for tracking people's door-accesses (https://fsektionen.se/admin/dorrar) is currently insufficient since it assumes that a functionary post has its regulated door-accesses for the entire occupation period. The Song Contest Team Leaders for example only have their accesses during the autumn semester (see https://fsektionen.se/dokument/504), but will technically keep their position for the spring semester as well.

The box where the positions are filled could be split into four, for each quarter (läsperiod). This problem only applies to a few positions though, so there should be a "apply to all periods"-function as well.

#1045 is a related issue.

Start at the admin door-access page at https://fsektionen.se/admin/dorrar and review related issue #1045. Define how a functionary position's access period should be represented across the four quarters, including an option to apply access to all periods. Done means positions can have quarter-specific access while unchanged positions can still use all periods.

Written by the indexing model from the issue text.