Prettier, stylelint, tslint, editorconfig, sitting in a tree

[kremalicious]

Make life easier by creating the basis so auto formatting and linting works in most code editors. E.g. in VS Code, having the prettier extension installed is all that's needed for auto-formatting on file save.

Those 2 new npm scripts execute based on the combination of all those config files:

# auto format all ts & css with tslint & stylelint
npm run lint

# auto format all ts & css with prettier, taking all configs into account
npm run format