Allows configuring postgrest from the db by setting config parameters
on the connection role. For example:
ALTER ROLE postgrest_test_authenticator
SET pgrst.jwt-secret = "REALLYREALLYREALLYREALLYVERYSAFE"
The above wWill set the `jwt-secret` config option accordingly.
SUPERUSER privileges are required for ALTERing role settings,
so this might not work on some cloud-managed databases.
This feature is enabled by default, for disabling it you can add the
following to the config file:
db-load-guc-config = false
steve-chavez