Fee Info in PaymentDetails

[TheBlueMatt]

It'd be nice to be able to fetch the fee-paid from PaymentDetails (both for outbound payments and inbound payments where the LSP took a fee off the top).

[G8XSU]

Needed in ldk-server as well, will assign to myself.

[tnull]

This is already available on master since #468:

ldk-node/src/payment/store.rs

Lines 45 to 51 in f0338d1

	/// The fees that were paid for this payment.
	///
	/// For Lightning payments, this will only be updated for outbound payments once they
	/// succeeded.
	///
	/// Will be `None` for Lightning payments made with LDK Node v0.4.x and earlier.
	pub fee_paid_msat: Option<u64>,

Closing as completed.

For inbound JIT payments you'll see the negotiated fee limits here:

ldk-node/src/payment/store.rs

Lines 349 to 357 in f0338d1

	/// Limits applying to how much fee we allow an LSP to deduct from the payment amount.
	///
	/// Allowing them to deduct this fee from the first inbound payment will pay for the LSP's
	/// channel opening fees.
	///
	/// See [`LdkChannelConfig::accept_underpaying_htlcs`] for more information.
	///
	/// [`LdkChannelConfig::accept_underpaying_htlcs`]: lightning::util::config::ChannelConfig::accept_underpaying_htlcs
	lsp_fee_limits: LSPFeeLimits,

This should be mostly equal to counterpart_skimmed_fee, but technically we only assert that the former is less or equal than these limits before claiming the payment.

[tnull]

Now opened #497 to add counterpart_skimmed_fee to the Bolt11JIT variant.