Global option to disable all LuaTeX warnings

[TomSteu]

In my opinion it would make sense to have a global way to disable all warnings about LuaTeX not being used. This includes the solution #49, but also for features that will otherwise just be ignored.

The reasoning is simple: TikZ-Feynman is widely used in physics, where the arXiv has become a widely adopted standard for preprints. These are often (if not mostly?) uploaded as LaTeX manuscripts, with pdf files being created on the server side using pdflatex. This alone sets a compelling standard for many people, not just me. Of course, TikZ-Feynman is still very capable to use with pdflatex, the only downside is that the build is flooded with hundreds of warnings, which drown out others that might be of more pressing importance. A global switch to silence them all would be useful -- it is not like we are unaware of the situation.