[X] Add possibility to specify never-expiring tokens in validation
[X] Decide in approach for handling values of additional claims, which right now are Strings but should be able to handle things such as Vec<T> as well
[X] lib-module-level API that uses V4 and takes/returns Claims and ClaimsValidationRules.
closes #17
TODO:
Strings but should be able to handle things such asVec<T>as wellClaimsandClaimsValidationRules.