allow query to overwrite state features

[robfitzgerald]

This PR gives the user the option to overwrite initial values for state features at query time. the user

• must be overriding an existing state feature by name
• must match the feature type of the existing (if it was a StateFeature::Distance, it should still be that)
• can ovewrite the initial value of the feature (go from 0.0 to 10.0 minutes initial time)
• can also overwrite the enum variant of the unit (go from Kilometers to Meters)

Added issue #185, that would help further protect against invalid overwrites (a percent should still be a percent).

Closes #145.

[nreinicke]

Yeah I like this feature and think it will be important for things like initial state of charge. When attempting to test this, I'm noticing that the units are getting set appropriately when passing in a custom state feature but I'm not seeing the initial value being updated. For example, if I add the following to our base query in the open street maps example notebook:

        "state_features": {
            "time": {"time_unit": "seconds", "initial": 6000}
        },

The resulting time comes out as 653 seconds:

If I don't inject this the time gets reported as 10.89 minutes and so it's using the right units but not the new initial value.

[robfitzgerald]

it's using the right units but not the new initial value

what's weird is the state model does reflect the new initial value in the screenshot above. wondering where this is getting ignored or overwritten. i think i need to check the initial_state function.

[robfitzgerald]

@nreinicke found that StateFeature::get_initial wasn't actually pulling from Distance|Time|Energy StateFeature initial fields, and would divert to CustomFeatureFormat::default() for those cases, for who knows why (i'm looking at you, @robfitzgerald 🙄 )

[nreinicke]

good find! just pulled the latest changes and it seems to be working as expected, thanks for adding this in!