Fiduswriter

**Features:**
* Split REGISTRATION_OPEN into REGISTRATION_OPEN and SOCIALACCOUNT_OPEN
* Allow multiple --python-path command line options

**Fixes:**
* Redirect correctly after canceled social account login

**Fixes:**
* Clean images based on image nodes, not figure nodes

**Fixes:**
* Add paragraphs to empty table cells
* Convert initial data correctly

**Major features:**
* Merge dialog for conflicts between offline/online users (thanks to anandksalien )
* Table captions
* Styling of epub navigation pages
* Prosemirror-py for server side handling of changes instead of separate json patch
* Django 3.1 upgrade
* Use jsonfields for json data in database
* IDs for tables and lists
* Support direnv for development
* Table/figure captions in the main editor so they can be styled
* dropdowns that don't create scroll bars

**Fixes:**
* Do not show figure/table placeholders when captions are hidden

**Fixes:**
* Translation updates (translations broke site)
* Allow docstyle selection
* forbid changing of marks in protected sections (from 3.8.29)