Mer devices: make device specific actions work

This fixes the device specific action buttons in device setting page for
Mer devices.

Fixes dabab8a (Merge branch 'mer-3.1' into next). See 2a3ef09 (Device
support: Make IDevice::executeAction non-const.)

Signed-off-by: Martin Kampas <martin.kampas@jolla.com>
Mer: Fix setting debugged process' environment

Fixes dabab8a (Merge branch 'mer-3.1' into next)

See 2259909 (Introduce the concept of a "device process".)

One conequence is that this makes debugging work again.

Signed-off-by: Martin Kampas <martin.kampas@jolla.com>
Remotelinux: Fix deploy config widget geometry

Signed-off-by: Martin Kampas <martin.kampas@jolla.com>
Mer: Cleanup UI forms

Eliminate redundant/annoying scroll areas, allow to line-wrap possibly
long file paths, remove extra spacing, remove redundant widgets, cleanup
layouting to allow proper geometry calculations, make wizards less
shaky, ...

Signed-off-by: Martin Kampas <martin.kampas@jolla.com>
Jolla QML designer plugin: replace XML metainfo with QML

Outdated since 80b46df (QmlDesigner.ItemLibrary: replace XML item data
with QML)

Note: actually this change has no effect as the QML designer is not
supported by Sailfish SDK at the moment.

Signed-off-by: Martin Kampas <martin.kampas@jolla.com>