Choosing a formatter for McStas

[Lomholy]

Sometimes when we make large components and work on them multiple people, the indentation gets mixed up. We use different coding styles and paradigms, which by themselves are fine, but when mixed they get confusing to read. This discussion is an extension of #2308 which showcased the default clang formatter.

I therefore propose that we choose a formatter that we accept to be used when working on mcstas components.

I propose that we either use the clang-format formatter or the astyle (Artistic style) formatter.

I will spend some time in the coming days, coming up with which settings could be used for a formatter, and showcase what this results in for a couple of different examples, namely the Monochromator_Bent components and the Union_mesh component.

Looking forward to hearing your thoughts on this!