Make Meeting Fields Editable

You should be able to do though the UI what advanced users can already do by editing the database: Decide what fields are "visible" and add "custom" fields.

When doing this, it would be nice to refactor the meeting_data table and separate the field definitions from the meeting data. How it is now, with for instance the field prompts and visibility defined but not used at the meeting level, and the field values defined but not used at the metadata level - is confusing and wasteful.

It might also be good to let the user make some of the standard fields uneditable - leaving fields open results in inconsistent data. It's not clear what's a subsection and whats a neighborhood and what's a land. Long range, it would be good to hide some of the fields, but that would require that the UI react to which fields are visible, and I'm not sure that's feasible.