Make Staking pallet using a proper Time module. (#4662)

* add new trait, still migration to make

* Apply suggestions from code review

Co-Authored-By: Kian Paimani <[email protected]>

* implement migration

* better naming

* fix test

* no longer require DeprecatedTime

* add test

* fix version

* upgrade only from kusama

* add test

* fix test

* Update frame/timestamp/src/lib.rs

Co-Authored-By: Bastian Köcher <[email protected]>

Co-authored-by: Kian Paimani <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>