* BE: limit contribution emails to CONFIRMED & one per user + add app context to EmailSender
* BE: handle EmailSender setup and start using flask request context
* todos: simple ones, removals & modifications to NOTE
* rem-todo: reduced markdown images are removed by sanitizer
* be todo: add user validation to create
* be todo: improve test_invide_api tests
* be todo: remove todo comment
* fe todo: set error messages on reducers
* fe todo: upgrade and enable react-helmet
* todos - remove uneeded
* fe todos: remove unecessary
* be: fix remaining staking contribution calculation
* Upgrade sentry sdk, replace all prints with flask logging.
* Upgrade node sentry to fix circular json error.
* Update frontend sentry versions to maintain parity and nab any fixes.
* Backend setup for proposal canceling.
* Cancelable in admin, update all states to properly reflect a canceled proposal.
* Replace REFUNDING stage with CANCELED and FAILED to distinguish between the 2
* Fix pending contributions showing up as needing refunds.
* Fix some refund cases.
* Dont show failed & canceled proposals on list view. Hide their filters.
* Show when proposal was canceled.
* Remove edit action, make cancel an explanation to contact support.
* Fix PR comments
* Fix issues from develop merge.
AMStrix
William O'Beirne
Daniel Ternyak