WIP: replace capnpronto with serde + bincode

[sobolevn]

Why is this PR marked as WIP?
Well, there's a problem I want to ask about.

Right now we can correctly serialize and deserialize all internal objects, except the fact that TypeVar's ids are not regenerated. This is needed to uniquely identify type vars and to make sure that there are no conflicts.

Old module had this code:

gleam/compiler-core/src/metadata/module_decoder.rs

Lines 140 to 155 in efc519c

	fn type_var(&mut self, reader: &schema::type_::var::Reader<'_>) -> Result<Arc<Type>> {
	let serialized_id = reader.get_id();
	let id = self.get_or_insert_type_var_id(serialized_id);
	Ok(type_::generic_var(id))
	}
	fn get_or_insert_type_var_id(&mut self, id: u64) -> u64 {
	match self.type_var_id_map.get(&id) {
	Some(&id) => id,
	None => {
	let new_id = self.ids.next();
	let _ = self.type_var_id_map.insert(id, new_id);
	new_id
	}
	}
	}

The first proposed solution by @HarryET #1912 had this logic: https://github.com/HarryET/gleam/blob/b46f227ac18f9bbe2e36de2a7c9b73505ba74282/compiler-core/src/metadata.rs#L22-L42

But, the code above is incomplete (it does not have types_value_constructors, values and accessors processing). It is also not very clean and will require constant modification.

The problem is that serde does not allow simple stateful deserialization. It has DeserializeSeed API which is not an easy API to use and to connect with bincode.

The second problem is that bincode@1.0 will soon be replaced with bincode@2.0 which will not have deserialize_from_seed API. So, I don't think that it is worth doing that as well.

I've also tried https://github.com/Marwes/serde_state to work with the global state, but it is unmaintained.

So, what should we do? :)
Tests are failing because of that.

Most of the credit for this change goes to @HarryET
Thank you!

Closes #1599

[HarryET]

Awesome to see this change back! Happy to have a look if you want but feel bad you've had to sift through that PR 🤣

[sobolevn]

I totally need an advice :)

[lpil]

Closing due to inactivity. Please feel free to reopen! Thank you