Update documentation "How-to-build", now that we are using alpaka

[ichinii]

Update documentation "How-to-build"
https://hz-b.github.io/rayx/Introduction/05-How-to-build.html#cloning-the-repository

now that we switched to alpaka. The How-to-build section in our documentation is outdated.

• List CMake configure options
• Test and update prerequisites for Ubuntu
• Test and update build steps for Ubuntu
• Let someone else confirm that the described steps work on Ubuntu
• Test and update prerequisites for Windows
• Test and update build steps for Windows
• Let someone else confirm that the described steps work on Windows
• Test and update prerequisites for Arch/Manjaro
• Test and update build steps for Arch/Manjaro
• Let someone else confirm that the described steps work on Arch/Manjaro
• Probably remove Fedora from the list
• Explain compiler and cuda compatibility
• Document compile.sh script

[Atraxus]

It might be difficult to get information on the build dependencies from developers who already have a working set-up. I will try to figure out what packages I installed on my Arch system for RAYX but I am not sure I will find exactly the needed ones.

I think the compile.sh script is not relevant to most developers. And those who want to use it will understand it.