feat: implement JSON rpc client and extractor for bitcoin

[DSharifi]

closes #1941

[gilcu3]

I have two (small) blockers related to the network requests:

• We are supporting only POST, but RPCs might also use GET I assume
• In the headers we only allow a single header. To have full generality, we should accept any number of them

[netrome]

Good stuff. Some thoughts from my end. My main concern is if it's too limiting to restrict us to one RPC call per inspector. Secondly I think we should use associated types instead of generics in the traits, that would be cleaner. But none of these are blocking, and both can be tackled separately or not at all.

[DSharifi]

I have two (small) blockers related to the network requests:

* We are supporting only POST, but RPCs might also use GET I assume

This first revision is only supporting the bitcoin core API which uses JSON-RPC. Json-rpc requests sent over HTTP are always POST per the spec.

* In the headers we only allow a single header. To have full generality, we should accept any number of them

This ask of multiple header is relevant to you, @netrome , since your PR is creating the config spec for authentication. I see your design also went with supporting only one header I currently don't see why we would need more than one header for authentication, but it's a simple change.

@gilcu3 Do you have a specific use case in mind for setting multiple authentication headers?

[gilcu3]

Approving as both blockers I had are not relevant, more context in thread

[netrome]

Thanks for updating to use associated types 🙏