Don't trigger deep pattern warning on non-pattern files

[andriokha]

I am using Pattern Lab Node v5.13.2 on Linux, with Node v14.16.0, using a Custom Edition.

Expected Behavior

This is regarding the warning that's emitted if you go beyond 3 levels deep when deeper nesting's enabled.

We don't have any patterns deeper than 3 levels, but we do store images in a subdirectory. That is, the structure is similar to

- molecules/
  - blocks/
    - media-block/
      - media-block.md
      - media-block.mustache
      - media-block.scss
      - media-block~variant1.json
      - media-block~variant2.json
        - images/
          - image1.jpg

I'd expect this to compile without warnings because there are no patterns nested deeper than 3 levels.

Actual Behavior

The following warning's emitted.

Warning:
A pattern file: xxx was found greater than 3 levels deep from yyy.
It's strongly suggested to not deviate from the following structure under _patterns/
[patternType]/[patternSubtype]/[patternName].[patternExtension]
or
[patternType]/[patternSubtype]/[patternName]/[patternName].[patternExtension]

While Pattern Lab may still function, assets may 404 and frontend links may break. Consider yourself warned. 
Read More: https://patternlab.io/docs/overview-of-patterns/

Is there actually any risk with our current setup? Does it make sense to explicitly look for patterns rather than any file before issuing the warning? If that's not workable for some reason (and assuming we're not doing anything dangerous) would it be possible to have an option to disable the warning? Currently we've increased the log level (as done in #1037) but ideally we wouldn't have to.

Steps to Reproduce

1. Set allPatternsAreDeeplyNested to true in patternlab-config.json.
2. Set up a pattern with the structure shown above.
3. Build pattern lab.

(And thanks for a fantastic project!)