feat: open up avalanche methods CP-9587

[gergelylovas]

Description

Opens up avalanche methods to allow external developers and dApps to interact with the P and X chains.
It exposes:

• avalanche_sendTransaction. When user signs the transaction, it is sent immediately. Prompts the user with an approval window.
• avalanche_signTransaction. Signs the transaction and returns the signed transaction to the caller. Prompts the user with an approval window.
• avalanche_signMessage. Sign messages using the X/P derivation path. Can be used to prove owneship of the account simiar to how personal_sign works for eth. Prompts the user with an approval window.
• avalanche_getAccountPubKey. Returns the the current account's evm and pvm public keys.

Changes

Change Core only method list.

Testing

Attempt to call the above mentioned RPC methods from a non Core and non localhost domains.

Checklist for the author

Tick each of them when done or if not applicable.

• I've covered new/modified business logic with Jest test cases.
• I've tested the changes myself before sending it to code review and QA.