Backport to 7.7: When thumbnail size is altered the height/width of the surrounding html should be changed (CMS7-6285)

When thumbnail size is altered the height/width of the surrounding html should be changed:

The thumbnails in the gallery (see screenshots li-a-height_cms.jpg and li-height_cms.jpg) are surrounded by an anchor tag (<a>) and an list item tag (<li>) which both have a set height of 100px and the li also has set width of 100px in a CSS file.
For the gogreen demo its https://cms.demo.onehippo.com/resources/org.hippoecm.frontend.plugins.gallery.ImageGalleryPlugin/ImageGalleryPlugin.css

Since its possible to change the thumbnail size in the console (see thumbnail-size_console.jpg), the size of the li and a tag should not be set via CSS but according to the size set in the console (via inline styling). This will prevent the name of the imagefile to overlap the image.(see images-in-dialog.jpg and images-in-navigation.jpg).
The height (and width) should be 40px bigger then the set maximum size of the thumbnail-image.

When its set to max 60px (as default) the li should have height and width 100px (as current) and the anchor should have height 100px.