Codechange: Build station and depot vehicle lists from shared order lists. (#11676)

The brings some performance advantages:

* No need to iterate all vehicles and check for primary vehicle as only vehicles that can have orders are listed.
* Shared orders only need to be tested once instead of for each vehicle sharing them.
* Vehicle tests only need to be performed on the first shared vehicle instead of all.

src/CMakeLists.txt

@@ -510,6 +510,7 @@ add_files(
     vehiclelist.cpp
     vehiclelist.h
     vehiclelist_cmd.h
+    vehiclelist_func.h
     viewport.cpp
     viewport_cmd.h
     viewport_func.h