refs TryGhost/Product#3609
- author and publisher styles were mixed up in mobiledoc
- made consistent for author coming after publisher for md and lexical
- updated renderer packages
- As a library, minifier should be subject to 100% coverage
- minor change to the code combining globbing and file reading into a single function for error handling any case where the files can't be found or read
- we could do more fine grained errors here, but that seems unnecessary given that the usecase is internal, not for user files at the moment
- added error case tests to capture all the uncovered lines
- wired up a basic minification package
- accepts config for css or js files and can concat and minify them into a single file for each type
- this will be used for generating merged css and js files for various cards, controlled by theme config
