Simplify nim bindings

[jtraglia]

I would like to simplify the Nim bindings before the big v2.0 release. This PR does the following:

• Remove the "zero overhead aliases" which I find pretty confusing.
  • I think one could argue that these are over-complicated & prone to issues.
  • When adding EIP-7594 support, I made several mistakes.
• Remove duplicate tests, only use reference tests.
  • The tests for each API (kzg, kzg_abi, kzg_ex) were too much.
  • It's okay to only run through the reference tests.
• Use a global KzgCtx like the other bindings do.
  • This is simpler & also less prone to mistakes.
  • Requires that free_trusted_setup is called on exit.

Some thoughts on this from our discussion on discord:

Opening as a draft until @agnxsh tests it.

I would also appreciate a review from @jangko, the author of these bindings.

[jangko]

LGTM. Besides loadTrustedSetupFromString, Nim actually can optimize it further via compile time mechanism to load baked in array from executable binary. But that better put into another PR.

[jtraglia]

@jangko Oh cool. Yes let's do that in another PR.

Any thoughts on the optimization issue on Windows? I've disabled compiler optimizations as a bandaid fix until we figure it out. I asked about it on Discord (in Nimbus's PeerDAS channel):

Also, I think I've run into a Nim compiler bug. For some reason, the Windows release build will crash when calling computeCellsAndKzgProofs. The debug build works and the release build with --opt:none works too. I spent a couple hours trying to figure it out. No issues on Linux either. Is there a Nim expert that could look into this?

To be clear, this happens when the high level wrapper function (computeCellsAndKzgProofs), not the ABI function, is called & it is not crashing due to anything the function is doing. I put an echo before the function was called and another at the top of the function. Only the first one printed.

[jtraglia]

Thank you @jangko for identifying the issue:

Maybe related to completeStruct pragma being absent from KzgCell? Because I see other types/struct are using completeStruct. Not completely sure though.

After adding this to the type, the Windows CI tests pass again.

[jtraglia]

This branch was tested by Agnish (nimbus dev) and confirmed it compiles & passes the reference tests. Going to merge.