Optional opt-out for Collection type generation

[MarkAtOmniux]

Hi team, the generate:types command generates types for every collection in my project, including types not intended to be used by the frontend. In order to reduce bloat, I plan to introduce a new field on collections and globals called excludeType. This field gets used in the configToJSONSchema utility to optionally exclude types from being generated. I was thinking of opening a PR but wanted to see if 1 - this is something that people would want and, 2 - if I should wait for v3 before PR'ing the change?