[Feature Request] Add delete post function (NIP-09)

[escapedcat]

Other clients offer this, i.e.:

• https://iris.to
  
• https://snort.social
  

Happy top help with this and create a PR if wanted/possible (I'm not sure about implications/context of nostr).

See: https://github.com/nostr-protocol/nips/blob/master/09.md

Looks like this has been prepared already: https://github.com/escapedcat/hamstr/blob/main/src/nostr/NostrStore.js#L122-L125