Decrease amount of git submodules

[yorickvP]

The following submodules currently exist:

ocaml:

• capnp-ocaml
• async_kernel
• rpc_parallel
• snarky
• ppx_optcomp
• tablecloth
• ppx_version
• prometheus

C:

• c-reference-signer

node:

• snarkyjs

rust:

• wasm-bindgen-rayon
• proof-systems

The ocaml packages can be handled by opam, the rust deps can be handled by cargo, and the nodejs deps can be handled by nodejs. We'll also figure something out for the c-reference-signer.

[yorickvP]

Produced o1-labs/proof-systems#612

[robinbb]

@yorickvP @balsoft @Firobe It seems this issue has not had work done in 9 days, though it is marked "in progress". Is it in progress? If so, what is the progress?

[yorickvP]

@robinbb progress was made at #11388