Include mandatory fields into sync

[koltyakov]

Some fields should always be included no matter were they requested explicitly or not.

Such fields are:

• ID
• Created
• Modified
• Author
• Editor

[koltyakov]

The mandatory fields are added. They automatically injected into the request.

Also, the code is refactored a bit to rely in explicit props instead of making a try using all and ignoring service fields.

This design decision is driven by the aspect, that it's not always only List fields can be synced, but also a nested object model props which do not exist in List/Fields metadata. E.g. file props or a lookup prop.