Refactoring management service to utilize CRDTs

[iakkus]

The management service was written at a time when the data layer was a simple key-value store. As a result, many data structures regarding the users, functions and workflows utilize ad-hoc prefixes to identify various pieces of information (e.g., list of functions and workflows; function code, requirements, zip data; workflow info, JSON description).

Besides the simple (key, value) pairs, the current data layer supports more complex data structures that are CRDTs, such as maps, sets and counters. The usage of these advanced data structures will simplify the management service code.

[iakkus]

This change, however, will be a breaking change, such that a separate mechanism would be needed to convert any legacy data to the new scheme. This mechanism could be an offline tool, such that it would be transparent to the user.

Alternatively, this can be done when existing users login again. In this case, the management service will have to have code that after a while becomes redundant. Furthermore, the GUI might need to be updated to notify the user about this conversion, because it might take some time to process.

I'd vote for the offline tool to make the conversion.

[manuelstein]

+1 for the offline tool and proper data design