Adding bitcode encoding/decoding to server fn IO

[arpadav]

bitcode has been on the top of rust ser/de benchmarks and would be great to use within leptos's server_fn.

On the implementation-side, one question: Encodes trait requires an error type, but bitcode can encode anything without error. I tried to do:

impl<T> Encodes<T> for BitcodeEncoding
where
    T: bitcode::Encode,
{
    type Error = ();

But am getting an error, since unit type does not impl Display. I just put a comment and made it type Error = String as a bandaid fix. Ideally it could be (), or perhaps if there was some blanket struct. Unsure what is preferred?

(I was told to modify the Error to be std::convert::Infallible here 4f81773 and this solves the issue above)

Tested on my end, but I'd like others to confirm. I did not see any particular places to put tests for server fn IO types, otherwise I can help populate those tests

[gbj]

Looks good to me! (one CI-related nit)

[gbj]

Can you also add this to the denylist down below? (see here)

[arpadav]

@gbj Added!

And I noticed that skip_feature_sets has ser/de combinations between serde, serde-lite, rkyv, and miniserde. I assume these are for Resource's? So there is no need to add bitcode here?