* migrate first distribution test to use simapp
* refactor test TestAllocateTokensTruncation
* migrate allocation test for distribution
* migrate TestCalculateRewardsBasic to simapp in distribution
* migrate TestCalculateRewardsAfterSlash to simapp in distribution
* migrate TestCalculateRewardsAfterManySlashes to use simapp
* migrate TestCalculateRewardsMultiDelegator to use ssimapp
* migrate TestWithdrawDelegationRewardsBasic to simapp
* migrate TestCalculateRewardsAfterManySlashesInSameBlock to simapp
* migrate TestCalculateRewardsMultiDelegatorMultiSlash
* migrate old delegation test
* migrate keeper test to simapp
* refactor all distribution to use simapp
Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>