Create parameter serializer and convert Infinity and -Infinity to np.inf and -np.inf

[anth-volk]

Fixes #115

This PR:

1. Converts "Infinity" to np.inf and "-Infinity" to -np.inf
2. Adds testing
3. Creates subschemas for the ParametricReform schema to explicitly support and validate three reform input types:

{
  "param": 15_000
}

{
  "param": {
    "2024": 15_000
  }
}

{
  "param": {
    "2024-01-01.2025-12-31": 15_000
  }
}

[nikhilwoodruff]

This looks good and yes conforms to what I'd expect the schema to be.

[anth-volk]

Will merge after tests pass, given addressing of all issues and pre-emptive approval from Nikhil