Create data encryption/decryption standard plus supporting APIs for wallets to implement

## Motivation

Many potential applications might prefer to encrypt end user data via a public key the user controls rather than encrypting via a user's password (i.e. lastpass), as passwords are a poor UX compared to a web 3 wallet. Metamask currently is the only web 3 wallet I'm aware of which offers the ability to decrypt via private key. Ideally Solana wallets should support this, and ideally all the wallets would use the same algorithm for obtaining a public encryption key and the same asymmetric encryption algo too. In the linked EIP you see a proposal for wallets to offer an RPC for encryption via `secp256k1` + `ECIES`.

## Details

Relevant discussion in Ethereum: https://ethereum-magicians.org/t/eip-5630-encryption-and-decryption/10761/128
Metamask SDK:
- encrypt: https://docs.metamask.io/wallet/reference/eth_getencryptionpublickey
- decrypt: https://docs.metamask.io/wallet/reference/eth_decrypt/

Open related issue in Backpack https://github.com/coral-xyz/backpack/issues/4241
Open related issue in Solana Mobile Seed Vault https://github.com/solana-mobile/seed-vault-sdk/issues/144
Closed related issue in Solana web3 repo https://github.com/solana-labs/solana-web3.js/issues/1367