Allow errorLevel="<int>" on individual files and folders

[olleharstedt]

This could be very handy for our legacy code-base where we apply Psalm step by step. Thoughts?

Example:

    <projectFiles>
        <directory errorLevel="8" name="controllers" />
        <!-- This applies errorLevel as defined for the whole doc -->
        <directory name="models" />
    </projectFiles>

There's a six year old issue here: #21

[orklah]

That could be interesting and I don't think it would be very hard to do.

If you're up to it, I'd suggest starting in Config::getReportingLevelForFile

[olleharstedt]

I might :)