Update code to consume the new RBToolsConfig for config access.

Review Request #13037 — Created May 10, 2023 and submitted — Latest diff uploaded




RBToolsConfig is now used throughout the codebase.
BaseCommand.config is now an instance of this, options now take this,
and base command support accesses state on this without the need for
conditional checks.

Options benefit the most. We can now get rid of all the custom
default= arguments on any option backed by a config key. The option
support has always based the default on the config, but only to reflect
values specified in config files. Since RBToolsConfig now manages all
defaults, the ones on options can be removed. That will happen in
another change, but the classes are prepared for it.

Unit tests pass.

I've been using this locally, and have used it to post this change and
other related changes today.