refactor: move Tags from server/no-meteor to node-app

[kieckhafer]

Resolves #5624
Impact: minor
Type: refactor

As part of our effort to separate our Reaction Admin from our Reaction Node API, we are moving our GraphQL services from their respective /imports/plugins/*/server/no-meteor/ folders into their new /node-app/{core-services|plugins}/* folder.

Updates also include future-proofing some existing code, including adding filetype extensions (and index.js to imports)

Breaking changes

Any custom plugins that import files directly from the Tags package will need to be updated.

Testing

1. Start the application and see that it works as it should.
2. See that you can add / remove tags from products, create tags, etc