Ubuntu: Fix cmake to copy qml files pre-build

REVIEW: 117896
BUG: 333075
Ubuntu: Fix the ImapSettings flickable

This fixes the view was not scrolling when OSK is visible.

REVIEW: 117924
GUI: make sure the composer always has a window title

Simply opening the composer as a new fresh mail, without replying to an existing
subject, would leave the window title uninitialized, which means that the user
would get an ugly "trojita" instead of a nice, localized "Compose mail".
Ubuntu messageListPage delete message

BUG: 333212
REVIEW: 117514