feat: stop cross compiling miniooni (#908)

See https://github.com/ooni/probe/issues/2119

While there, shrink the Makefile to only export the minimum
set of rules to comfortable build using GHA.

CLI/go-build-alpine

@@ -12,6 +12,9 @@ export CGO_ENABLED=1
 export GOARM=$GOARM
 export GOOS=$GOOS
 export GOARCH=$GOARCH
-go build -o ./CLI/$PRODUCT-$GOOS-$OONIARCH \
-	-ldflags='-s -w -extldflags "-static"' \
-	$GOLANG_EXTRA_FLAGS $PACKAGE
+for PACKAGE in $@; do
+	PRODUCT=$(basename $PACKAGE)
+	go build -o ./CLI/$PRODUCT-$GOOS-$OONIARCH \
+		-ldflags='-s -w -extldflags "-static"' \
+		$GOLANG_EXTRA_FLAGS $PACKAGE
+done