Change subfolders for optimisations from site to architecture

### Are there any linked Issues or Pull Requests?

Umbrella: #424
PR: #767

### Brief description

We have a-lot of duplication of the scripts due to the site name. Originally the intention of the site folder was to contain within it the ideal optimisations, given it's specific hardware architecture requirements.
However, to run the scripts, we are forced to duplicate the scripts for other sites, even though they require no specific site changes.
If we move from sites to hardware architecture, and allow the site to point at specific architecture as required, we maintain the origonal principle, but reduce the duplication and overhead updating all of the scripts together.

To begin with we will have:
* minimum
* cpu
* gpu

With space to expand to allow for example:
* cpu-ex
* cpu
* gpu-nvidia
* gpu-arm

Where these are then set by the sites specific marco, to dictate the type of architecture these will use.

This means CPU sites which all use EXs no longer need to have duplication given the site name, however with scope to allow custom versions of the scripts if the sites require it.

### Further details of the issue.

_No response_