CI: Allow skipping our GHA workflows with `DISABLE_GODOT_CI` variable #7530

Job	Run time
📊 Static checks / Code style, file formatting, and docs	45s
🍎 macOS / Editor (target=editor, tests=yes)	6m 29s
🍎 macOS / Template (target=template_release)	3m 5s
🐧 Linux / Editor w/ Mono (target=editor)	4m 3s
🐧 Linux / Editor with doubles and GCC sanitizers (target=editor, tests=yes, dev_build=yes, scu_build=yes, precision=double, use_asan=yes, use_ubsan=yes, linker=gold)	17m 6s
🐧 Linux / Editor with clang sanitizers (target=editor, tests=yes, dev_build=yes, use_asan=yes, use_ubsan=yes, use_llvm=yes, linker=lld)	8m 55s
🐧 Linux / Template w/ Mono (target=template_release)	1m 54s
🐧 Linux / Minimal template (target=template_release, everything disabled)	49s
🍏 iOS / Template (target=template_release)	3m 9s
🌐 Web / Template (target=template_release)	1m 39s
🤖 Android / Template (target=template_release)	4m 1s
🏁 Windows / Editor (target=editor, tests=yes)	10m 5s
🏁 Windows / Template (target=template_release)	8m 24s
🪲 Godot CPP / Build and test Godot CPP	9m 34s
	1h 19m 58s

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