Add application-specific information to phase (e.g., timesteps) in JSON output

[lifflander]

What Needs to be Done?

We want to be able to match up timesteps in NimbleSM with phases IDs.

[nlslatt]

I think we should add a new std::unordered_map<PhaseType, std::shared_ptr<nlohmann::json>> to LBDataHolder that holds the phase-level (i.e., not object-specific) user-defined json. We should dump the string for the appropriate phase into the json file within a user_defined block alongside the phase id, tasks, and communication that are already in the json file for each phase. Avoid use of the initializer list constructor for json strings.

[nlslatt]

We still need to figure out a good interface for this.

[nlslatt]

@lifflander @nmm0 Any thoughts on an interface to this?

[lifflander]

@JacobDomagala I think for this issue we should add a new interface to the PhaseManager that can add user-defined data:

thePhase()->addUserDefinedData(phase_id, key, value)

For this to output correctly to file, we need key and value to be jsonable. We should store this data in the LBDataHolder by phase_id. We need to add both readers and writers for this in the toJson and the constructor I think for LBDataHolder.

[nlslatt]

@nmm0 The ability to add user-defined phase-level information (like t or dt from the application) is now on develop.