* used manager's Add function in more places
* exit when ctx.Done is received in archivePruner go routines
* fix manager tests
* fix data race
* added more gpm function in manager and removed manager from a util function
* closed unused channel and stopped ticker after context is done
* added log statements
* used context.Done inside function instead of stopper channel
- added manager to wait for all go routines to end before exit
- code refactor
- renamed Manafer to Interface and GoRoutineManager to GroupManager
- replaced some go routine calls with manager Add func
- added unit tests for manager
