armbian-next: post_build_image: run hook first, then write to CARD_DEVICE, then compress, in that order

- compress *all* present output images, not only .img
- remove 7zip compression & hostdep
- squash a few shortcircuits (yeah, this late in the game...)

extensions/image-output-ovf.sh

@@ -113,4 +113,5 @@ function post_build_image__920_create_ovf() {
 
 	display_alert "Done, cleaning up" "${EXTENSION}" "info"
 	rm -rf "${full_vmware_dirname}"
+	return 0
 }