Expose the amount held on our end of the channel

[andrei-21]

To properly display the amount the user received, I need to know the amount held on our end of the channel, even if it is not enforceable on-chain or not spendable on Lightning.

ChannelDetails::outbound_capacity_msat is not enough because it takes the channel reserve into account. But adding the reserve back does not work for balances below the reserve.

[MaxFangX]

Some more context from Discord: link

I would also be content if Balance displayed the amount that is projected to be lost to dust, so we can include it in our balance calculation.