Add a new bumpforceclosefee rpc endpoint to the wallet server.
Move the logic from the lncli level to the wallet server rpc level.
This is more in line with a proper client-server design.
wallet lncli: use new bumpforceclosefee endpoint.
Besides using the new bumpforceclosefee rpc endpoint we also enable the
bumping of taproot anchor channels.
This commit moves `DetermineFeePerKw` into the `Estimate` method on
`FeePreference`. A few callsites previously calling `DetermineFeePerKw`
without the max fee rate is now also temporarily fixed by forcing them
to use `Estimate` with the default sweeper max fee rate.
This refactor aims to house the CalculateFeeRate function in a more
"shareable" location. It used to be a non-exported function inside
of rpcserver.go. However, other routines, such as FundPsbt inside
of walletkit_server.go, could also rely on the same fee calculation
functionality. So we move the function to rpc_utils.go and export it,
and we will reuse it in the FundPsbt workflow in a future PR.
With the middleware handler in place, we now need to add a new gRPC
interceptor to the interceptor chain that will send messages to the
registered middlewares for each event that could be of interest to them.
