[qml] added Mer.State/StateMonitor Qml component

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
tool: allow to write property

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
tool: basic support for property writing

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>