quotaholder: Unify included data in overLimit errors
Replace `available' with `usage' and `limit' in NoQuantityErrorto make it similar to NoCapacityError.
quotaholder: Allow resolving empty commissions
When resolving a pending commission, handle the case where the commissionhas been issued with no provisions.
quotaholder: Add migrations
Migration 0001 should be faked on an existing database.Migration 0002 adds new fields.Migration 0003 populates the new fields based on the old ones.Migration 0004 deletes unneeded fields and tables.
Revert quotaholder's name to quotaholder_app
In order to facilitate migrations.