Grunt production removes binary files

[t-book]

Expected Behavior

Building static files should copy all needed files

Actual Behavior

Binary files get deleted when running grunt production.

Steps to Reproduce the Problem

1. follow the docs for frontend develeopment setup
2. run grunt production

Specifications

• GeoNode version: all

[t-book]

ref #5444 ... as lib directory has binary files which are not managed by package.json we change here to only delete subfolders:

https://github.com/GeoNode/geonode/blob/master/geonode/static/gruntfile.js#L37-L39

    clean: {
      lib: ['lib/']
    },

or check if we get rid of clean completely (and just overwrite with new files)