[util] statefs::qt namespace for utility fns

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
moving util.hpp to the common includes dir

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] moved to separate .so

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[util] inout implementation, docs

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[build] statefs-qtX libraries, docs

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[examples] using inout statefs loader

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