Split the text format parser into its own crate

[fitzgen]

lalrpop and its generated code can take a while to compile, and I'd like to add a moat between it and the rest of the project.

We should move src/text/{grammar.lalrpop, parser.rs, actions.rs} to a new crate: crates/text-parser. The crate name should be wasm-webidl-bindings-text-parser. Otherwise it should basically remain the same. We can re-export its functionality in src/text/mod.rs.

[ghost]

I would like to try this one.