Per-account colours and quiet hours, thumbhash for media

* Per-account colours when multiple accounts
* Per-account quiet hours (applies to messages and calls both)
* Send and decode thumbhash thumbnails for media messages
* Tap on phone numbers and urls in Command UI as links
* Set display name to that of contact (not self) for incoming call
* Fix conversation style notifications from group chats
* Require device unlock rather than account password to change password
* Reply to a PM should also be a PM
* Merge fix for "only rings three times" issue on some devices
* Include note to self in share menu
* Delete thumbnails when file deleted or message moderated
* Fix for when there is a file from previous install "in the way"
* Optional MANAGE_EXTERNAL_STORAGE support to read/overwrite files from previous installs
* Do not show raw geo URI when it is the whole message body
* Performance fixes for WebXDC and blurhash
* Initial support for XEP-0221
* Use same libwebrtc as Conversations and Snikket
* Do not crash when a WebXDC file is sent but not attached to a thread
* Make text-multi and jid-multi work at all for Command UI
* Make result fields tall enough to show all items
* Fix Unicode offsets in fallback indication