Group issues to folders in a different way

[gudmdharalds]

Currently we group problems found by the folder the individual file being scanned belongs to. The downside of this is that sometimes there are a number of problems that are due to one plugin or theme, scattered over a number of files, with only a few problems per GitHub issue created.

Instead of grouping them to the final folder, we should allow a new grouping method, by folders higher up in the hierarchy, i.e. by plugin or theme at a maximum. We would do this by going through the hierarchy, merging problems higher and higher up, stopping just before reaching any sub-folders of plugin or theme folders. However, this should not be without limits: Before problems are grouped to folders higher up in the hierarchy, we check if a certain maximum is reached, and if so, we stop the process.

This will lead to issues being grouped together, but in a way that is more user-friendly.