tetragon/windows: Add windows compile as a ci step

[ExceptionalHandler]

Description

This PR adds a CI step to cross compile tetragon.exe for Windows on Linux.

[mtardy]

hey, why don't you use the existing facilities with a new GOOS (like with GOARCH) or something like that? I'm not sure to understand why we need a whole new Makefile.

[ExceptionalHandler]

Of course that is the easy change.
I am following precedent set by how tetra.exe is built for Windows and Darwin.
Also, a new make file lets us add packaging and ebpf building targets later without disrupting other makefiles.

[mtardy]

just doing GOOS=windows make tetragon should build tetragon for windows

[mtardy]

I see that you got inspired by the CLI thing. I would favor the existing build target we have for tetragon. wdyt?

[mtardy]

I would suggest this instead of creating a new Makefile, please also add ./tetragon.exe just after ./tetragon in the clean: target.

Suggested change

	run: make tetragon-windows
	run: |
	GOOS=windows GOARCH=amd64 make tetragon
	GOOS=windows GOARCH=arm64 make tetragon

[ExceptionalHandler]

I have made this change.

[mtardy]

Thank you, also:

please also add ./tetragon.exe just after ./tetragon in the clean: target

I imagine you can do as a followup, no big deal