Evg-module-manager

- Update documentation to call out Python 3.7.1 dependency.

- Add save-local-config subcommand.
- Support reading configuration from local file.

- Add several new git subcommands to support a more flexible workflow.
- Replace `create-branch` subcommand with `git-branch-create` subcommand.
- Replace `update-branch` subcommand with `git-branch-update` subcommand.
- Replace `commit-queue` subcommand with `evg-commit-queue` subcommand.
- Replace `patch` subcommand with `evg-patch` subcommand.

- Add support for Python 3.7

- Add documentation site.

- Fix create patch not configurable in Linux