Support blob data for presets

[kunalarya]

We can use any data format we want, e.g. RON, TOML, or JSON.

RON is a bit easier to map 1:1 to Rust objects, by definition, but isn't standard outside the Rust ecosystem. JSON can be difficult to edit/debug and without easy commenting support can complicate things like troubleshooting version differences. TOML is a nice middle ground.

A few open questions:

• How do we want to store floats and float arrays. Storing as text is kinda nice for human consumption but loses information.
  • Plan of action therefore will be to store as hex (wrap floats in something that implements Serialize and Deserialize for hex strings).