Class Throttler implements the bruteforce protection for security actions in
Nextcloud.
It is working by logging invalid login attempts to the database and slowing
down all login attempts from the same subnet. The max delay is 30 seconds and
the starting delay are 200 milliseconds. (after the first failed login)
The OCSResponse differs from other responses in that it defaults to
XML. However we fell back to json by default.
This makes sure that if nothing is set we don't pass anything.
Which defaults then to the controllers default (which is often 'json')
but in the case of the OCSResponse 'xml'.
