VIP: Remove RLPList

[iamdefinitelyahuman]

Simple Summary

Remove the builtin RLPList function.

Motivation

My understanding is that this function was put in place for, and served a very specific purpose related to the ETH 2.0 deposit contract. With a specific version of Vyper forked, verified and frozen for said contract, I see no need to keep this function as a part of the language.

Specification

1. Remove RLPList from vyper/functions
2. Remove the test cases
3. Remove the section in the documentation

Backwards Compatibility

It is a breaking change, but I highly doubt it will affect any existing projects.

Copyright

Copyright and related rights waived via CC0

[fubuloubu]

I see this change overall as good, because the RLP decoder is really not what most people want, rather they want #1406. So, this change should come after we finish that one.

[jacqueswww]

Approved; should be replaced by ABI - encoder / decoder.

RLP List isn't necessary anymore; and its a very error-prone part of the codebase.

[iamdefinitelyahuman]

Closed by #1872 and #1975