A command for autoclosing / synching issues

The maintainer of the repo might keep the issue open (for whatever reason) but fix the publiccode.yaml file anyway, in that case publiccode-issueopener should detect that and close the issue.

Doing would mean checking and processing every repo all the times, instead of just the repos with bad publiccodes, so that probably needs to be a separate command that we can run whenever we feel like synching the issues - less frequently than the normal run.

Related to #5