TypeScript: Remove callback from types in 5.x

[jankapunkt]

In release 5.x (#194) we dropped all callbacks, so types should reflect that, too. PR should target only release-5.0.0

[shrihari-prakash]

@jankapunkt could you remove the PR to remove callbacks? #211

[jankapunkt]

@shrihari-prakash did you mean "review"?

[shrihari-prakash]

Haha yes :)

[jankapunkt]

All changes are now public at https://node-oauthoauth2-server.readthedocs.io/en/latest/?badge=latest