Add Unreal Engine 5.2 release packaging tools

[aurebidart]

Fixes: #

About

This PR adds public release tooling for packaging Project AirSim with Unreal Engine 5.2 on Linux.

It introduces scripts to:

• Build and collect the approved ProjectAirSim, Drone, and Rover plugins.
• Install those plugins into an Unreal project and update its project and packaging configuration.
• Package Unreal environments through BuildCookRun.
• Create release ZIP archives with an embedded build manifest, a JSON manifest sidecar, and a SHA-256 checksum.
• Validate the expected Unreal Engine version and required packaged artifacts.

Release orchestration, credentials, runner configuration, and private repository mappings remain outside the public repository.

How Has This Been Tested?

• Ran the release tooling unit test:
  python3 -m unittest discover -s tools/release/tests -v
• Compiled the Python tools with python3 -m py_compile.
• Validated both shell scripts with bash -n.
• Verified the command-line interfaces of both shell scripts with --help.
• Verified the rebased changes with git diff --check.

A complete Unreal packaging run was not performed because it requires an Unreal Engine 5.2 installation and the corresponding build environment.

Screenshots and videos (if appropriate):

N/A — this PR adds command-line release tooling and has no user-interface changes.