WIP use two copies of c-kzg

[michaelsproul]

Proposed Changes

This uses some nasty hacks on my fork of c-kzg to enable two copies of the library to be linked: one with the mainnet spec, and one with the minimal spec. We can then select between them at runtime.

The main complication is that the C library wants to use the same symbol names for both libraries, which is worked around by:

• Using a different name for the resulting library (ckzgmin vs ckzg).
• Using objcopy to rename the public symbols when the minimal spec is enabled. A ckzgmin_ prefix is added.
• Using some regexes to modify the c_kzg_4844.h header so that the function stub names match the renamed symbols in the object file.
• Using some Rust import directives to rename the ckzgmin_ prefixed names back to the names without prefixes, so that the hand-written code that references them remains correct regardless of minimal/mainnet spec usage.

See the trusted_setup_minimal.rs for a basic test that shows the two libraries working independently (deserializing the minimal JSON into the mainnet JSON or vice versa will fail).

TODO

If we decide to take this approach:

• The crypto/kzg library has to be thoroughly refactored to use type-level selection between minimal and mainnet specs. Like EthSpec, but probably not EthSpec due to the circular dependency.
• We would need a version of objcopy that works cross-platform. Maybe cargo-binutils.
• There might be some other stuff that's broken. I wasn't quite sure if I needed to rename the internal symbols or remove them with something like --discard-all.

[michaelsproul]

Closing in favour of ethereum/c-kzg-4844#312