aliasing, hashmaps/hashsets, serde_json::Value, 1-tuples, i128/u128

[jurij-jukic]

• includes support for aliases, e.g. pub type GroupId = String; in Rust becomes type group-id = string; in WIT
• includes support for HashMaps and HashSets, e.g. HashMap<String, Role> becomes list<tuple<string, role>>, and HashSet<NodeId> becomes list<node-id>
• includes support for serde_json::Value, where it's aliased in WIT as type value = string;, and in TS as unknown
• includes support for 1-tuple structs, GroupPermissions(pub u64) becomes an alias type group-permissions = u64;
• includes support for i128/u128 → string, since WIT doesn't support 128 bit integers

[nick1udwig]

lgtm ⚡