New features:
* Less padding to the right of drop indicator
* Ability to set font
* alternateText - Set alternate text for button display
* sizeToContents - Width will adjust to fit all contents

Fix dropdown indicator color

Fix bug where QGCComboBox { model: ListModel would not work correctly

Update to the QGCComboBox to use a textRole in the case where it's availble.

Some small theme colour fixes.

Updating the items to be inline with the theme.

Fix height

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

On 5.7 and 5.8 somethings this would happen:
* The menu would be ordered incorrectly due to bug in Instantiator
* The menu would be positioned incorrectly

Also correctly set implicitHeight on QGCTextField

Android done.

UI Tweaks for all mobile platforms.

This reverts commit bf31c808.

Made then the same size of toolbar cell height