Update autotest.cmd

- Removed the output while writing the preseed configs
- Allow overwriting the DATADIR with a one line change
- Allow specifying a testsuite just like in autotest.sh
- Restore the development config after testing

@DeepDiver1975 mind running it on jenkins once, just to be sure
@th3fallen want to test this once?
I only silenced the echo for writing the autoconfig files. there is no need to print this, but as per your strike I think you noticed that aswell ;)