(Maint) Refactor retrieving the indirection in http handler

Pass the full indirection object into do_* methods instead of just the name.
This is a better access point for getting what these methods need and reduces
duplication.
(#22893) Make handler check whether remote requests are allowed

The http handler will check whether an indirection allows remote requests
before performing any operations.
(#22893) Disable remote requests for key termini

These don't make sense to use remotely since they manage private keys.
(Maint) Remove no-op rescue clause
Merge pull request #2003 from pcarlisle/ticket/22893-control-remote-requests

Ticket/22893 control remote requests