WIP: Add common fighter attributes

[NickCondron]

I'd like to include the common fighter attribute values in this repository. Many of these values are useful to have an exact reference. For example weight, friction, jumpsquat_frames, aerial landing lags, turn_duration, etc. However, many are also not useful. There are also some attributes whose purpose is unknown.

These values were generated directly from game files using this fork https://github.com/NickCondron/meleeDat2Json/tree/update-attributes based on various sources for known attributes and their types.

This PR is a WIP because I'd like your feedback on how best to organize the data for inclusion in this repo. I have 32 json files just like the mario.json file in the PR, and I created an example of the corresponding rust module could be organized.

1. Some types are f32 in the game data, but are integers in practice. Should their types be changed to an integer type? (For example the *_landing_lag attributes)
2. Should I reduce the required size of the attribute if it is never exceeded? For example, maybe the landing lag fields should be u8 because it's smaller and they never exceed 255 for any character.
3. Should I remove unknown and/or useless fields?
4. Should I join the json files into one large file?

[hohav]

I like the JSON, but I wonder about the Rust structs. I'm guessing this stuff will be super niche, so it might be premature to go that far. What about just adding the JSON to start with, and then we can see what use cases develop? That would also postpone the need to hammer out the nuances you've mentioned for now.