Support skip attribute in RlpEncodable derive macro

[mattsse]

Describe the feature

There are use cases where being able to skip fields during rlp encoding is useful:

#1101

Currently, we don't support this in the RlpEncodable derive macro.

TODO

add rlp(skip) field attribute support for RlpEncodable macro that should work the same as serde(skip).

Additional context

No response

[leruaa]

I would like to take this on

[mattsse]

I guess we'd need rlp(default) as well for the RlpDecodeable macro

[leruaa]

Yeah, I found this:

reth/crates/common/rlp-derive/src/lib.rs

Lines 12 to 16 in d86c989

	//! This library also supports up to 1 `#[rlp(default)]` in a struct,
	//! which is similar to [`#[serde(default)]`](https://serde.rs/field-attrs.html#default)
	//! with the caveat that we use the `Default` value if
	//! the field deserialization fails, as we don't serialize field
	//! names and there is no way to tell if it is present or not.

but looks like it's not implemented at all.

Do we just need rlp(default), or also rlp(default = "path") like in Serde?

[mattsse]

yeh I believe this was not implemented before the fork.
imo rlp(default) should be sufficient, path would be nice though.

[leruaa]

I will see how to add path, I guess #1116 can be merged in the meantime.