feat: Rollup mode

[jcw-]

Check List

• Tests has been run in packages where changes made if available
• Linter has been run for changed code
• Tests for the changes have been added if not covered yet
• Docs have been added / updated if required

Description of Changes Made (if issue reference is not provided)

• Adds support for only allowing queries to hit rollups.
• Adds support for running a separate instance of cube.js to refresh rollups and set the api instance of cubejs to a mode where it doesn't try to check for rollups being current and doesn't try to create or refresh them.

[jcw-]

@paveltiunov Thoughts? I'll put up a commit with documentation updates later (and fix the linting and tests), but I've tested this out and added error handling and ensured it's all opt-in functionality.

[paveltiunov]

@jcw- Hey Jc! Looks great! Thanks for contributing it!