[rebalance] : allow setting both --in-target-outbound and --out-target-inbound on rebalance

[BhaagBoseDK]

is it possible to add feature to set both --in-target-outbound and --out-target-inbound on rebalance and lower of the two is used (or even optional --use-higher default false).

use case when using tags, you may want to set in-target-outbound capacity/2 but at the same time you may want to use --out-target-inbound CAPACITY*3/4 (i.e. you want to rebalance 50:50 but in the process do not want to drain all liquidity to remote).