[tracking]: merge `custom-channel` features into `lnd` and `litd`

[dstadulis]

Tracking issue for
lightninglabs/lightning-terminal#848

Legacy Issues

https://github.com/lightningnetwork/lnd/issues/8769

lightningnetwork/lnd@4f2c75f
https://github.com/lightningnetwork/lnd/commit/4f2c75f62047579f249ed5914042a0cc6337f342/hovercard
lightningnetwork/lnd#8509
lightningnetwork/lnd#8632
lightningnetwork/lnd#8660
lightningnetwork/lnd#8771
lightningnetwork/lnd#8509
lightningnetwork/lnd#8632
lightningnetwork/lnd#8660
lightningnetwork/lnd#8771

[dstadulis]

the entire team will likely distribute testing scope to the parts of the code base they're experienced with