relay-builder: Plugins

[v0l]

Description

Adds a plugin system for write/query

Notes to the reviewers

Checklist

• I followed the contribution guidelines
• I ran just precommit or just check before committing
• I updated the CHANGELOG (if applicable)

[yukibtc]

Awesome, thank you! Cherry-picked at f21ffbd

I've done some small adj. during cherry-picking, like removing unnecessary Box: Arc<dyn WritePolicy> instead of Arc<Box<dyn WritePolicy>>.

[v0l]

Nice, im using it for wss://hole.v0l.io that i posted about today on nostr https://git.v0l.io/Kieran/nostrhole/src/commit/94616e69205adc98c21c01a85deeeb90d80702b0/src/main.rs#L231-L239