Operator: revise Registries concept

[eparovyshnaya]

Operator implementation reside on Registries, that are the parties eligible to load and store resource under operator's work. Currently they are stateful for known reasons.

There is also a prototype concept of Operator Workspace growing under internal api. It's purpose is to serve more or less the same need.

Right now theirs implentations are a bit entangled and aware of each other. This part should be revised and possible reimplemented.

[eparovyshnaya]

LOC sample project has been shut down