* Moved server/lib/utils.js to Typescript

* moved _app.js to Typescript

* Moved _error.js to Typescript

* Added argument for custom props in _app and _error

* Moved _document.js to Typescript

* updated one test

* Updated types and added a validation for _document props

* Improved types

* Fixed some types

* Updated AppType

* Fixed some tests

* Added missing import

* Removed a not very useful type

* Fix missing type

* Move @types/styled-jsx

* Fix typescript errors