port to ts

[fratzinger]

continuing from original PR: #654

This is just a plain port to typescript. Just a refactor, nothing should break but imports from require(feathers-hooks-common/lib/...) or require(feathers-hooks-common/types)

Strategy: Make it a major version, just to be sure. Release it as premajor first.

Issues: closes #656
PRs: closes #662, #646, #634, #661, #658, #655, #652, #650, #647, #644

Next steps:

• Update index.d.ts #662 already included in this PR
• Fix API calls #646 already included in this PR
• Fix the preventChange hook (allowing to use falsy values) #634 already included in this PR
• Dove Support #623 I would like to add this to TS version
• Add setField hook from feathers-authentication-hooks #546 I would like to add this to TS version

[fratzinger]

released as v6.0.0