QMCPACK build instructions for ARM

[ye-luo]

I only need to build hdf5 and newer cmake beyond the script shows.
In the script, I treat armclang as clang to workaround cmake.
Message was sent to arm to improve the cmake compatibility.
C++14 is fine.

[prckent]

Thanks.

1. A manual entry is needed for visibility and additional explanations.
2. I would prefer this is a manual entry only. It is a non-production system that our cmake handles fine. (e.g. We don't have build scripts for x86 and only have them for a few important systems.).
3. Please also cite + link to the existing ARM page on QMCPACK.

[ye-luo]

Good point. A manual entry is better. I will move it to the manual and keep it there only.
3. I don't like some hacks on the ARM page. I will ask them to align with us.

[ye-luo]

I moved the recipe to manual. But I'm hesitating to cite the link in our manual. First, they should follow us not the opposite. We are the official one. Second, links may easily get changed.

[prckent]

(I could find two sources of build instructions https://developer.arm.com/products/software-development-tools/hpc/resources/porting-and-tuning/building-qmcpack-with-arm-compiler and https://gitlab.com/arm-hpc/packages/wikis/packages/qmcpack . The second is user contributed and might be the original source. We could PR updated instructions to this wiki e.g. when v3.6.0 is out.)

[ye-luo]

@prckent. Correct, I got email from ARM that we can update the gitlab and then they will update the webpage accordingly.