migrate build system to earthly: supports building core, start and angular for all supported platforms. tauri still missing

cmds/winkext-test/main_linux.go

@@ -0,0 +1,10 @@
+//go:build linux
+// +build linux
+
+package main
+
+import "log"
+
+func main() {
+	log.Fatalf("winkext-test not supported on linux")
+}