Add partial support for Proactive rules

[bmorrissirromb]

Issue #, if available:
Part of #400

Description of changes:
This partially implements issue #400. Config does not support Proactive evaluation modes for Organization rules. Only single-account rules support EvaluationMode arguments.

So, this change allows single-account (non-Organization rules) rules to use proactive evaluation modes.

This will be lumped into the 0.18.0 release. I am not planning to do a 0.17.12 release.

The CLI will have two new options:

• rdk create will support an argument for --evaluation-mode and store it in the parameters.json file
• rdk deploy (but not deploy-organization) will this feature by reading EvaluationMode from parameters.json.

In addition to this change, there are a few minor changes lumped in here:

• CFTs are now maintained as YAMLs, not JSONs, because YAML is just better.
• Carlo and Nima are listed as active maintainers. JDJ is moved to a former maintainer.

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