Merge pull request #2555 from tnull/2023-08-have-get-route-take-params

Have `get_route` and `Route` take `RouteParameters`

diff --cc lightning/src/ln/channelmanager.rs
Simple merge

diff --cc lightning/src/ln/functional_test_utils.rs
Simple merge

diff --cc lightning/src/ln/functional_tests.rs
Simple merge