[LSST|dm-users 691] Warning: use "config" instead of "root" in config override files from now on

[Russell Owen]

As of RFC-62 and DM-3630 (which I just merged to master) you should use “config” in your config override files for the config object you are overriding, instead of “root”.

For now we do support backwards compatibility: if you have old files that use “root” then you can load them, but you will get a warning message printed to stderr. At some point we are likely to remove this backwards compatibility.

The main code change is in pex_config, but I also updated the config files in many packages.

— Russell