refactor: the CLI package needed an update regarding handlebars

[mfranzke]

Partly resolves #1239

Summary of changes:

Integrated handlebars packages as the successor of mustache.

• Removed packages @pattern-lab/starterkit-mustache-base, starterkit-mustache-acidtest, starterkit-mustache-bootstrap, starterkit-mustache-foundation and starterkit-mustache-materialdesign from dependencies, as those aren't necessary to get referenced (and aren't possible to get selected from the npm create pattern-lab process).
• Corrected the packages/cli/readme.md on the default packages to be installed.
• Corrected the tests regarding the newer handlebars and twig packages instead of the outdated mustaches ones (see aspect one).
• Corrected handlebars engine package links, they were still pointing to an older version of that package (adapted the links from https://github.com/pattern-lab/patternlab-node/tree/dev/packages/edition-node)