feat: Add NEAR Protocol plugin

[serrrfirat]

Risks

N/A

Background

This is the first PR that introduces NEAR Protocol plugin to eliza.

What does this PR do?

Introduces:

• Wallet provider that returns the current NEAR balance.
• Swap functionality given the input and output contract addresses through Ref.finance.
• Native token transfers.
• New env variables for NEAR Protocol

What kind of change is this?

Features (non-breaking change which adds functionality)

Why are we doing this? Any context or related work?

To introduce basic NEAR Protocol functionality to eliza, which could be further extended.

Documentation changes needed?

My changes do not require a change to the project documentation.

Testing

Changes can be tested by providing a near address, public key and private key in .env, and asking eliza to swap, transfer and provide wallet details.