Expose `UserConfig::channel_handshake_limits::min_funding_satoshis`

[tankyleo]

For the server use-case, I am quite sure people will want to bump the current default of min_funding_satoshis: 1000 set in rust-lightning

[tnull]

Hmm, probably, but maybe we'll want to expose most other limits, too (i.e., most of ChannelHandshakeLimits, except for the ones that we currently intentionally override depending on other settings, e.g., trust_own_funding_0conf/force_announced_channel_preference/ etc). There are also a few related issues, so it would make sense to work out a Config API that doesn't just add everything to the main Config object.

[vincenzopalazzo]

I agree with @tnull here, probably we should not duplicate the fields but use the type of rust-lightning directly? And then use the Config as a facade for changing the value?

This was really what I wanted to do in lampo when I was working on it, and then the only difficult part would be keeping in sync all the set & get functions, but nowadays, probably with AI, it would be simpler?