Put external dependencies into dedicated directories

tubio-frontend-nuxt-app/assets/README.md

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+# ASSETS
+
+**This directory is not required, you can delete it if you don't want to use it.**
+
+This directory contains your un-compiled assets such as LESS, SASS, or JavaScript.
+
+More information about the usage of this directory in [the documentation](https://nuxtjs.org/guide/assets#webpacked).