Desktop accessibility: Main enhancements

Bug report

• Fix the keyboard shortcuts
• Make the UI scalable
• Support for a spellchecker including regional languages
• Plugin for subtitles during calls
• Changeable community based languages
• Allow to navigate the account list using keyboard and fix the screen reader properties
• Fix the tips on the main page for a screen reader
• Fix the call overlay to be fully accessible using a keyboard and a screen reader
• Add keyboard navigation inside the conversation list
• Add support for the open-dyslexic font
• Allow to read and navigate messages using keyboard and a screen reader
• Make the settings fully accessible
• Proper labeling of the account creation
• Add shortcut remapping
• Fix the popups not closing with escape
• Fix the chat view cursor traps
• Fix the good to know popup
• Fix photobooth focus
• Make the conversation list accessible by keyboard navigation