[tests] refactoring and unifying

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
set global config dir

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
needs qtaround >= 0.2.0

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[qml] error signal passes variant map instead of string

It is used to pass reason (should be standard), message etc. It also
compatible with previous semantics

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