Updating .gitignore to just say public

Previously had many files/subdirectories broken out in the `.gitignore`; seems the idea is just to ignore the entire directory, which can be done with just the one line.

Does not address any open issue; just addresses potential confusion over what should/shouldn't be ignored in `public`.

Author: zacanger

.gitignore

@@ -1,22 +1,10 @@
 node_modules/
 .DS_Store
-public/index.html
-public/styleguide.html
-public/styleguide/html/styleguide.html
-public/css/*
-public/data/*
-public/fonts/*
-public/js/*
-public/images/*
-public/patterns/*
 latest-change.txt
 patternlab.json
 .sass-cache/*
 /sass-cache
 source/images/Thumbs.db
-public/styleguide/css/static.css.map
-public/styleguide/css/styleguide-specific.css.map
-public/styleguide/css/styleguide.css.map
 source/css/style.css.map
 .idea/
-public/styleguide/
+public