1. Manually request focus for input fields and show keyboard
This is needed when targetting API 28 which doesn't give focus anymore
automatically like it used to be.
Closes#1505
2. Remember keyboard states across screen rotations
This also upgrades the emoji library and gets rid of the
KeyboardAwareLinearLayout that is still a relict from the time when we
were using Signal's emoji implementation.
3. Move soft keyboard showing/hiding into UiUtils
