actually use custom content handler for previewers and on both the complex and simple reminder forms
surround the name with a fieldset so that it's not just floating in the form randomly
ignore forms that can't be found
clean global timeouts separately so that the validation error shows up in the correct field
update start reminder options to include All Cases and change wording
update Start Reminder label
allow external language picker to manage reminders languages
also check to see if the translation_doc is None
Merge pull request #3847 from dimagi/reminders-ui-updates

Reminders Updates