Make invoice and bulkpayments into links instead of dropdowns

Removing either of those manually on a record is likely to cause
inconsistency between the models. Instead, they should be cancelled
using the proper interface. Therefor, make it impossible to remove
them in the admin interface, replacing it with a link (they can of
course still be removed at the SQL level if things are really broken)
Track fees for paypal payments

We already did this for Adyen payments, and it's good to know for followup
in our budget works if nothing else...
Show paypal fee in transaction overview
Add tool to backfill paypal fees into the database

Used to backfill fee information for all transactions where we haven't
collected that information before. Once this info is on all transactions,
this script will no longer be useful...
Fix formatting of status output