Handle store walls like other walls

Description

Store walls should use the same code and components the other walls use.

TODOs for this issue (possible in multiple MRs):

• Write SQL triggers and migration to keep data synced in two states.
• Check if entries with milestone != 1 can be removed
• add the SQL code as migration
• Handle posting to store wall in backend: Permissions and side effects (bells, store log etc.)
• Use <Wall> component on store page
• Remove all backend usages of fs_betrieb_notiz
• Remove unused code and clean up
• Remove triggers and old table after releasing to prod
• Maybe enable pictures for store wall

Evidence

Solution

Links / references