Set warning level for build on Windows

[ronald-jaepel]

Let's discuss at the next Core-Dev meeting which warnings we want to include in the output. In the past, Sam set the warning level to level 4 (commit) to show all warnings, to use this to eliminate sources of warnings. A decision we need to make as a team is: do we want to:

• always show all warnings, or
• should we reduce the warning level for e.g. Release builds and keep them for Debug or a specialized "maintenance" build setting.

[jbreue16]

Dev call discussion:
We should first check how many and how easily we can fix the warnings.
Or exclude some warnings like the unsigned / signed int comparisons, which would also be an easy fix, just change to signed int.
Unsigned int discussion:
https://soundsoftware.ac.uk/c-pitfall-unsigned.html#:~:text=C%20and%20C%2B%2B%20are%20unusual,that%20can%20never%20be%20negative.
https://www.sandordargo.com/blog/2023/10/18/signed-unsigned-comparison-the-most-usual-violations
Und es gibt noch mehr, aber auch Gegenstimmen:
https://graphitemaster.github.io/aau/

@daklauss would be a good candidate to look into this