Validation status badge in software page

[sebbalex]

Is your feature request related to a problem? Please describe. As discussed in #365, see the excerpt below:

Suboptimal solution proposed As discussed with @alranel @biancini, it might be way faster to insert a link in the footer of the sw page pointing to a URL built something like: https://publiccode-editor.developers.italia.it?path=https://github.com///publiccode.yml&action=validate so that the responsible of the software can directly see the errors, fix them in the editor, export the new file and push it in the repo. The link should kindly say that the validation did not pass (I would suggest avoiding phrases like ERROR). Maybe in order to do this we could insert an indication of the last good parsing time and, in case that time is in the past, insert the link discussed above.

Describe the solution you'd like That publiccode feature is now live, I would discuss here about inserting a small badge in related software page that will display the validation status and link to publiccode-editor when it fails. From there it will be possible to understand the reasons for this.

cc @libremente

Describe alternatives you've considered none

Additional context none