Add config options to hide parts of the eComma UI

Fixes https://edgeryders.eu/en/open-ethnographer/task-4118

Adds config form in admin/config/ecomma to en/disable all ecomma tabs
Blocks are disabled in ecomma_block_view, with the exception of the comment block.
Since that isn't generated in the ecomma module, we disable it in JS instead.
Only show 'add comment' form when comment thread or cloud display is on
Merge pull request #1 from danohuiginn/hide_ui

Add config options to selectively hide parts of the eComma UI. Fixes https://edgeryders.eu/en/open-ethnographer/task-4118