* Use advanceWidth to get the with of the original text

Co-authored-by: Nicolas Werner <nicolas.werner@hotmail.de>

# Previous commits:
#   5949173b Add function to force focus on InputDialog input field
#   9482ac4e Allow explicit selection of SSO method
#   ab05e2d8 Mobile message input (#962)
#   12a6da01 If you replace the txn id, replace a string the length of the txn id...

* making userName_ an AbstractButton should make it play nicely with the ListView

* make Avatar an AbstractButton

* make userName_ in Reply.qml an AbstractButton

* use alias for avatar background color and fix margin of username in reply

It seems that you need to manually destroy created objects... Great...

fixes #898

That way we can autohide the scollbar if needed, it should fix some
jumping issues, it makes it possible to flick on mobile, etc.

Some related bugs:

https://bugreports.qt.io/browse/QTBUG-75223
https://bugreports.qt.io/browse/QTBUG-44902

fixes #941

This makes them less annoying when scrolling or accessing the popup
menu.

See also #860

fixes #435

fixes #519

Fixes messages in room flickering and being stuck

fixes #760
relates to #770
relates to #789

Showing the bootstrap state and showing there are unverified devices is
still missing.

- Fixes scrolling to an event not being reliable
- Adds new /goto command that can open URLs, go to events, or go to message indexes.
- Refactored ChatPage::handleMatrixUri() to contain the handling originally in Nheko::openLink(), and makes it return a boolean based on whether the URL was handled internally or not.