MIRA Integration

I've implemented the schema to support integration with MIRA models as discussed at the TA2 WG call today.

https://github.com/AlgebraicJulia/ASKEM-demos/blob/master/Mira/mira.jl

Output:
```json
{"V": [{"nameV": "v1"},{"nameV": "v2"},{"nameV": "v3"},{"nameV": "v4"}],
"P": [{"subject_P": 1,
"nameP": "p",
"rateP": 1.0,
"lawP": "const"}],
"D": [{"outcome_D": 1,
"nameD": "d",
"rateD": 1.0,
"lawD": "const"}],
"NC": [
{"subject_NC": 2,
"outcome_NC": 3,
"nameNC": "nc",
"rateNC": 1.0,
"lawNC": "linear"},
{"subject_NC": 4,
"outcome_NC": 1,
"nameNC": "return",
"rateNC": 2.0,
"lawNC": "linear"}],
"CC": [{"subject_CC": 2,
"control_CC": 3,
"outcome_CC": 1,
"nameCC": "cc",
"rateCC": 1.0,
"lawCC": "MAK"}],
"GCC": [{"subject_GCC": 2,
"control₁_GCC": 3,
"control₂_GCC": 4,
"outcome_GCC": 1,
"nameGCC": "gcc",
"rateGCC": 1.0,
"lawGCC": "generic"}]
}
```
The next step is to get models from the MIRA team and then do stratification on them.