Proposal to remove mina_signature_kind packages and move to mina_compile_config

[martyall]

the mina_signature_kind library provides a kind of compile time configuration that is as brittle as the mlh configuration we are working to remove. The usage of

• src/lib/signature_kind/testnet/mina_signature_kind.ml
• src/lib/signature_kind/mainnet/mina_signature_kind.ml

unnecessarily duplicates the codebase's executables in several places:

• src/app/cli/src/mina.exe splits into src/app/cli/src/mina_{testnet, mainnet}_signatures.exe
• src/app/archive/archive.exe splits into src/app/archive/archive_{testnet, mainnet}_signatures.exe
• src/app/rosetta/rosetta.exe splits into src/app/rosetta/rosetta_{testnet, mainnet}_signatures.exe
• src/app/rosetta/ocaml-signer/signer.exe splits into src/app/rosetta/ocaml-signer/signer_{testnet, mainnet}_signatures.exe

As we move away from compile time configuration, it as also possible to mix runtime configuration from one network with one of these builds in a way that it incoherent. I would propose that we

• remove the signature_kind package(s)
• remove the relevant sum type to mina_compile_config and make signature_kind a field there
• remove all of these duplicated executables and supply proper configuration for the remaining one

[martyall]

I have a branch off features/even-less-compile-config which does exactly this

https://github.com/MinaProtocol/mina/tree/martin/remove-mina_signature_kind

[martyall]

related to #15538