Build: Remove Form Validation localization files

The new dictionary reads the values from "lib" so there is no need to
copy them to the dist folder.
Merge pull request #3376 from nschonni/v4-cleanup-validation-dictionaries

Build: Remove Form Validation localization files
Combine Bootstrap CSS with Base

- Replace Boostrap copying with a concat with base SCSS
- Trim trailing commas
- Updated templates for new single base CSS