Fix integration tests
Generate swagger docs
Add test for moving a task between buckets
Add check for bucket limit when updating a task
Add fixture to ensure a bucket with a high limit will never exceed the limit
Refactor bucket limit check into seperate function
Add test for creating and fix
Fix unexported field
Add error in case a task was added to a bucket which has its limit already exceeded
Add migration to add new task field
Add limit field to buckets
Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/api/pulls/652
