feat: implement the nostr protocol

[github-tijlxyz]

Hello,
The nostr protocol is a open protocol that can be used to publish articles. You can find more information about the nostr protocol at github.com/nostr-protocol/nostr . This pull request tries to implement nostr's long-form content (NIP-23) into the miniflux feeds.

This PR implements:

• The user can input a nostr: user identifier link (it supports dns based links (NIP05) and bech 32 encoded links (NIP19) nprofile or npub.
• The server can load the nostr profile and profile picture, and the server can laod nostr posts
• The markdown parser parses nostr links using goldmark-nostr

below is me trying to explain what I have done to implement nostr into miniflux.

I started the base implementation from the internal/reader/handler/handler.go file, in which I added sections to the CreateFeed and RefreshFeed functions. I tried to integrate as best as possible with your code but I know this is probably not the right way to do it, I am happy to hear your opinion about how to best structure this with the existing miniflux code.

In addition to that:

• To execute nostr actions I'm using the widely used go-nostr library.
• I made a new nostr.go file and folder, which houses the nostr miniflux implementation.
• The subscription finding code is implemented from here
• The icon fetching code is implemented from here

Thank you

miniflux-showcase-final.mp4

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Do you follow the guidelines?

• I have tested my changes
• There are no breaking changes
• I really tested my changes and there is no regression
• Ideally, my commit messages follow the Conventional Commits specification
• I read this document: https://miniflux.app/faq.html#pull-request

[jvoisin]

I'm not convinced that adding a nostr client to miniflux is a good idea: adding support for nostr sounds like a first step towards adding support for twitter, bluesky, pinterest, mastodon, …

[github-tijlxyz]

Of course implementing nostr is a pretty big change compared to other simple sites and things. But nostr is a very open protocol with I think lots of potential, and viewing it in this format along other services would be great.

And, note that we are only implementing nip23 which is the specification for long form content. NOT the twitter-style content.

[asilentdreamer]

I'm not convinced that adding a nostr client to miniflux is a good idea: adding support for nostr sounds like a first step towards adding support for twitter, bluesky, pinterest, mastodon, …

While I don't use nostr and have no opinions on this PR, bluesky and mastodon offer rss feeds for every user. Nostr is probably one of the few platforms that are open but don't offer rss feeds which probably is not possible due to their architecture.