iRODS data storage integration

[wpbonelli]

We should support direct iRODS access (via https://github.com/irods/python-irodsclient) as before. Probably easiest to expose nested commands (e.g., plantit terrain pull, plantit irods push, plantit s3 pull).

[wpbonelli]

Need to make sure of compatibility with the scanner R pi OS since iCommands don't work, and we still need a more performant upload solution

[wpbonelli]

For iRODS we should support both keyword auth and environment file in the default location (~/.irods/irods_environment.json). Also need to support tickets (Computational-Plant-Science/plantit#225) as per the docs here

[wpbonelli]

Mostly implemented as of 1be38a3, pending resolution of ticket questions here