some people (me) have a large amount of prefs and moving from ref pds to
tranquil ment i lost a few of these. so in this pr i bumped the max
prefs to 1000 and made it configurable via the config
This is particularly useful in nix to avoid having to put secrets in
your configuration (or use some workaround) - but is probably quite
useful in other environments too and is a nice part of allowing either
environment or toml configuration.
To do this, I've had to split up the providers so as to provide
individual environment keys - I'm sure there's some clever macro that
could do this in fewer lines and more complexity
