Upgrade PROJ dependency version

[adamlm]

Summary

CARMA currently uses the default PROJ version that comes with Ubuntu 20.04, which is version 6.3.1. This is 3 major versions behind the latest release, so we should upgrade if possible.

Additionally, the PROJ apt package does not come with a PROJ4Config.cmake, so we are forced to download a PROJ4Config.cmake file maintained in a repo unaffiliated (as far as I know) with the PROJ project. The latest version of PROJ does not have this issue.

Furthermore, PROJ 6.3.1 uses antiquated CMake conventions and does not support being incorporated into projects via add_subdirectory().

Affected packages:

• lanelet2_extensions (in usdot-fhwa-stol/autoware.ai)
• intersection_model (in usdot-fhwa-stol/carma-streets)
• autoware_lanelet2_ros_interface (in usdot-fhwa-stol/autoware.ai)
• message_services (in usdot-fhwa-stol/carma-streets)

Reasoning for new functionality

See above