Add encrypt / decrypt to NIP-07 feature set

[nostrdev-com]

Hi guys

Per our discussion the other day, we are really happy to see NIP-07 support for Fedi Mods - it is a real step forward for secure enablement of nostr apps on mobile, particularly on Apple phones.

However, the implementation is not actually sufficient for most nostr web apps - the majority of which need to be able to decrypt and encrypt, as well as to sign stuff.

We would really like to see NIP-07 support for these APIs:

async window.nostr.nip04.encrypt(pubkey, plaintext): string // returns ciphertext and iv as specified in nip-04 (deprecated)
async window.nostr.nip04.decrypt(pubkey, ciphertext): string // takes ciphertext and iv as specified in nip-04 (deprecated)
async window.nostr.nip44.encrypt(pubkey, plaintext): string // returns ciphertext as specified in nip-44
async window.nostr.nip44.decrypt(pubkey, ciphertext): string // takes ciphertext as specified in nip-44

Backlink: https://git.nostrdev.com/sigit/sigit.io/issues/180

[nostrdev-com]

This tool might be helpful for testing: https://github.com/neilck/nip07-tester