Analyse files included in users submission

[AydinHassan]

It would be nice for checks to have access to all the files involved with a users submission. I'm not really sure how we'd do this - probably by parsing it. Some things to think about:

• Would we include Composer libraries in these files?
• How would we differentiate between user files and vendor files?
• We could parse includes and requires but what if user uses composers autoloading features, would we have to parse the composer.json?