add: stateless utilities to achieve full statelessness

[agnxsh]

Adds the Stateless Tree types as well helper functions that allow nim-eth-verkle to do the following things:

• build a prestate tree from the Verkle Proof (root hash)
• build a poststate tree from the State Diff
• construct the path for the partial view of the trie
• be able to verify that the partial view is correct using IPA and Multiproof, using the Verkle Cryptography backend added in Constantine.

Types may get refactored while implementing. Tried to make the most meaningful function names to avoid confusion.

Documentation is not yet ready, but I have tried to add in-line comments as much as possible

[advaita-saha]

@agnxsh
I think this should be better if shifted from inside the eth-verkle/tree/ipa to eth-verkle/ipa
Since the part we are going to add, helps in statelessness and not exactly core tree operation.

What's your suggestion ?

[agnxsh]

@agnxsh I think this should be better if shifted from inside the eth-verkle/tree/ipa to eth-verkle/ipa Since the part we are going to add, helps in statelessness and not exactly core tree operation.

What's your suggestion ?

okay makes sense

[agnxsh]

looks ok to merge

[agnxsh]

Ready for review, 1 verkle error file consisting of verkle error types, maybe needed in future for integration. Tests pending, will do in next passes, and subsequent fixes whenever needed.