factor out solc JSON interface crate (#264)

The differential testing framework will make a second consumer. There
seems to be no re-usable Rust crate for this. But we already have
everything here, just needs a small refactor to make it fully re-usable.

- Mostly decouple the solc JSON-input-output interface types from the
`solidity` frontend crate
- Expose the JSON-input-output interface types in a dedicated crate

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

crates/solc-json-interface/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "revive-solc-json-interface"
+version.workspace = true
+authors.workspace = true
+license.workspace = true
+edition.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+description = "Rust bindings for the solc standard JSON and combined JSON interface"
+
+[features]
+default = ["parallel"]
+parallel = ["rayon"]
+resolc = [] # The resolc binary adds a bunch of custom fields to the format
+
+[dependencies]
+revive-common = { workspace = true }
+
+anyhow = { workspace = true }
+rayon = { workspace = true, optional = true }
+semver = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }