Typescript rewrite

[dwightjack]

Tasks associated to this PR:

• Codebase rewrite in TypeScript
• types can be imported singularly as named imports or via the default import as the VueTypes namespace
• The default VueTypes object is a class with static members. This makes it easier to extend it in TS and ES6+.
• Create a custom copy of the VueTypes object (Setting sensibleDefaults globally before they're used in components #48)
• Update documentation
• test with Vue 3
• CircleCI config