Namespace config of CLI under proctor

[olttwa]

As an admin,
I don't want existing config of users to be accidentally used when running proctor. Currently, CLI has config with keys EMAIL_ID and ACCESS_TOKEN. Since these are common keys, user might have them set as ENV vars.

When proctor runs, it might pick preset config without user's knowledge.

In order to avoid such behavior, we can namespace config under PROCTOR_. Example: PROCTOR_EMAIL_ID and PROCTOR_ACCESS_TOKEN