Bug 34108+40266: Add scripts to check for needed toolchain updates
Checking toolchain updates can be done with the following commands:
- make list_toolchain_updates-geckoview
- make list_toolchain_updates-application-services
- make list_toolchain_updates-android-components
- make list_toolchain_updates-fenix
Closes #34108 (closed), #40266 (closed).