SettingsAccessor: Make environmentidFromMap static

Change-Id: I16564c95769f3bb3af6b096aff2658e1232df35e
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
SettingsAccessor: Move findBestSettings to SettingsAccessorPrivate

Also rename it bestSettings()

Change-Id: I0d9053d6429b0bd4e51ab9320f114e0a750dd77c
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
SettingsAccessor: Change readFile to return a QVariantMap

Change-Id: Ifb886a9ff1ae89063af2ce303f28baf0e92a3ba4
Reviewed-by: Daniel Teske <daniel.teske@digia.com>