consolidate mutexes

[yakra]

https://github.com/yakra/DataProcessing/blob/869e35c1d4c3cb729b3475619163071c3ecc8d9b/siteupdate/cplusplus/classes/TravelerList/mark_chopped_route_segments.cpp#L92-L105

https://github.com/yakra/DataProcessing/blob/869e35c1d4c3cb729b3475619163071c3ecc8d9b/siteupdate/cplusplus/classes/TravelerList/mark_connected_route_segments.cpp#L178-L201

2 mutexes per HighwaySystem & 2 per Route, used back-to-back. Could consolidating to 1 each save time by performing fewer lock/unlock operations?

[yakra]

• [x] Even if not consolidating (or just in the interim), Route::use_list_name and the like can handle the mutexes itself, and be easier on the eyes here. And maybe even save us some dereferencing?
• [x] For connected routes, we know r1 and r2 must be in the same ConnectedRoute & thus the same system. Therefore we can insert & erase both lookup1 and lookup2 in tandem within the same lock/unlock operations.
• After switching over to std::string-based fields, erase from the unused sets first, then use std::move to insert into the in-use sets (see https://github.com/TravelMapping/DataProcessing/issues/466#issuecomment-1378118302).
  • [x] lookups
  • [ ] labels

[yakra]

• [ ] For connected routes, we know r1 and r2 must be in the same ConnectedRoute & thus the same system. Therefore we can insert & erase both lookup1 and lookup2 in tandem within the same lock/unlock operations.