Improve channel endpoints

Possible improvements:
- [ ] open-channel should take a push amount parameter
* CLN: https://lightning.readthedocs.io/lightning-fundchannel.7.html
* LND: https://lightning.engineering/api-docs/api/lnd/lightning/open-channel
* Note, LND only supports sats for push amount, so we'll only support this everywhere
- [ ] list-channels should return the current Channel state (opening, normal, closing, etc)
* Note, this requires research how to properly categorize the channel status across implementations
- [ ] CLN-JRPC: https://lightning.readthedocs.io/lightning-listpeerchannels.7.html
- [ ] CLN-GRPC: https://lightning.readthedocs.io/lightning-listpeerchannels.7.html
* Note, must wait for next CLN which will include [ListPeerChannels support to the gRPC endpoint](https://github.com/ElementsProject/lightning/commits/master/cln-grpc/proto/node.proto)
- [ ] LND-GRPC: https://lightning.engineering/api-docs/api/lnd/lightning/list-channels
- [ ] list-channels should take an include "closed_channel" boolean parameter
- [ ] check if channel state changes are properly propagated through the SSE channel
- [ ] properly document the endpoint https://github.com/fusion44/blitz_api/blob/71ad84e70449daf2fa7cdcdb8a7ca4b4bac5acad/app/lightning/models.py#L392