[devel] default property implementation

AnalogProperty and DiscreteProperty are available to be used by c++
providers

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[property] pass shared_ptr with setter

Otherwise it is possible to code logic when update() can be called after
property has been deleted

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
statefspp and inout refactoring

Signed-off-by: Denis Zalevskiy <denis.zalevskiy@jolla.com>
[api] Basic Writer is taken from inout

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