Code cleanup of 08-wasm etheruem light client

[gjermundgaraba]

A final tracking issue for code cleanups to be done before the 08-wasm ethereum light client can be considered finished.

Add items here that will not be done in each individual PR to keep them moving a little faster.

• Either remove config.rs (and the typenum dependency) or rewrite client_state and consensus_state to compile-time sized and clean up config.rs
• Try to find a way to get rid of most, if not all, of the wrapped types in wrappers.rs (context: most of them are due to a seeming lack of tree_hash_root implementation on certain types, and tree_hash_derive not working in different scenarios). There might be a way to replace them with a few generic implementation if we are lucky 🙏 - as an alternative, maybe we can fix this in tree_hash_derive and get it upstreamed.
  • Union has some types they use for things like this: https://github.com/unionlabs/union/tree/main/lib/ssz/src/types (note: these types are compile-time sized, and if we end up doing that, we should also look alloy which has some of these types already too)
• Clean up ethereum_utils::base64. The structure, API and everything there is very verbose and tacky. Hopefully many of those types can be made more generic or otherwise easier to deal with. If not, at least make the code nicer...
• Either use ensure for all assertions, or remove it entirely. Can also consider if this could/should be a macro. (done in refactor: remove ethereum-utils and use ethereum sub-folder #186)