feat/near chain signatures support

[EdsonAlcala]

Description

This PR adds support for the NEAR protocol chain signatures, that allows a NEAR protocol account to control other accounts/addresses across multiple chains.

In order to enable the chain signatures support a NearKeyPairWalletProvider was required.

The PR also includes an example bot.

The following actions contain the functionality of the NEAR protocol chain signatures:

• get cross chain address
• get cross chain public key
• sign payload

Tests

• Added unit tests
• Testet prompts

Sign payload

Chatbot: typescript/examples/langchain-near-chatbot/chatbot.ts
Network: near-testnet
Setup: Users will be able to create a NEAR account

Prompt: sign me this payload "0x470637f6dcc98931d6d22afa2b491c20caf0c3ba595d707606fe7915c30ef0a7" using chain signatures 

-------------------
The signature result is big_r: 02ACE91E6368E5859640CB8E988D70E6C1551E3B8AEC897084C5A2797EF606CCE8, big_s: 3A84B3C0C157FFE0AC271A07F6ABB4BA8821E010F359FAEE05D82796122926F2 and recovery_id: 0
-------------------

The payload has been successfully signed. Here are the signature details:

- **big_r**: 02ACE91E6368E5859640CB8E988D70E6C1551E3B8AEC897084C5A2797EF606CCE8
- **big_s**: 3A84B3C0C157FFE0AC271A07F6ABB4BA8821E010F359FAEE05D82796122926F2
- **recovery_id**: 0

Let me know if you need any further assistance!

Get cross chain public key

Chatbot: typescript/examples/langchain-near-chatbot/chatbot.ts
Network: near-testnet
Setup: Users will be able to create a NEAR account

Prompt: what is the cross chain public key for the account sample.testnet

-------------------
Computed public key for account id sample.testnet, network near-testnet and derivation path account-1 is 0433cea8fa3b41fa277d16af5895aca4bcea550470a40dfaa4aaff3d7eafeb5b1bf13e9b6d8e55a3f2ecba326a3e79002d601835a0b16848b040653360e4ba411d
-------------------
The cross-chain public key for the account "sample.testnet" on the NEAR testnet with the derivation path "account-1" is:

**Public Key**: 0433cea8fa3b41fa277d16af5895aca4bcea550470a40dfaa4aaff3d7eafeb5b1bf13e9b6d8e55a3f2ecba326a3e79002d601835a0b16848b040653360e4ba411d

If you need any more help, feel free to ask!

Checklist

A couple of things to include in your PR for completeness:

• Added documentation to all relevant README.md files
• Added a changelog entry

[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 1 Sum 2

[EdsonAlcala]

hey @murrlincoln, any comments on this PR? Thanks

[EdsonAlcala]

@CarsonRoscoe let me know what are your thoughts. Best

[EdsonAlcala]

@CarsonRoscoe @murrlincoln I would like to ask you what is the criteria to merge and review PRs. Considering more recent PRs like #665 was merged before this one.

In general this PR has been open since March 13, that means after 36 days we are still here waiting and I have applied all your changes and suggestions.

No more changes have been required from our side.

If there are doubts or suggestions I'm happy to jump on a call and discuss about it. On the other hand, if the PR is not up to your coding standards or is not welcome you can also let me know. Because I have been constantly rebasing and merging and there is not clarity with it. I mean not even the pipeline has run.

[EdsonAlcala]

@CarsonRoscoe @murrlincoln Is this really the way to treat contributors?

[EdsonAlcala]

@CarsonRoscoe @murrlincoln any updates?

[EdsonAlcala]

any updates on this? @CarsonRoscoe @murrlincoln

[EdsonAlcala]

any updates on this? @CarsonRoscoe @murrlincoln