how many terms to display in the submission portal per env context term

[aclum]

Alicia suggests 20-50 for env_broad_scale, ~100 for env_local_scale and env_medium. Justification is crude comparison to GOLD pathway information, user experience with a list format and for now we'd still allow users to enter their own terms.

For reference GOLD has 3 values for ecosystem, ~50 ecosystem categories, ~300 ecosystem type, ~600 ecosystem subtypes, ~700 specific ecosystems.