Draft: New action to reset config for specified proposal via webservice

Description

This was discussed recently - do we want, along with the ability to modify proposal config through the webservice, a way to reset it and go back to using the default config? I thought I'd write a quick prototype.

How Has This Been Tested?

TBD

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.

Reviewers

@schmidtp @ahmedk