[BROKEN]Add support for Apple Silicon (M1) build

[GustavoSilvera]

Description

There are several reasons why one might want to build CARLA on the M1 devices, not least of which is the incredible performance they house in a tiny form-factor. Here I present some changes that I needed to build CARLA on my M1 MAX machine.

• Allow >clang-8 building
• Unified Linux and Mac .sh scripts as Unix build scripts
• Add necessary flags to make LibCarla && make launch && make package in x86_64 Apple (Run on rosetta)
• Add necessary flags to make LibCarla && make PythonAPI && make check in arm64 (runs natively)
• Does not change the Linux/Windows build
• Add documentation for Mac build (see Docs/build_mac.md)

Fixes #150 (but specifically for M1 devices)

Where has this been tested?

• Platform(s): MacOS 12.1, Linux (Ubuntu 21.04), Windows 10
• Python version(s): Python3.8 - Anaconda
• Unreal Engine version(s): 4.26-carla (modded by Carla)

Possible Drawbacks

• Unforeseen challenges with CARLA in multiple architectures
• Additional maintenance with CARLA for MacOS users
• Unable to build PythonAPI in x86_64 mode
• Unable to build PythonAPI with -ljpeg and -ltiff for now
• Need to make LibCarla twice, once in x86 mode and once in arm64 mode

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This change is 

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would update our CHANGELOG.md based on your changes.

[GustavoSilvera]

Made a mistake in the Github pr process. My bad. Reopening in #5086