fix: split staking reserve acc by staking denom

[dongsam]

Description

closes: #220

Tasks

• [x] Add AddressType, DeriveAddress
• [x] Refactor StakingReservePoolAcc, to using DeriveAddress and StakingCoinDenom
• [x] Add TotalStakingsRecords
• [x] Update Invariant for TotalStakingsAmount
• [x] Deprecate global StakingReserveAcc
• [x] Set default ReserveAddressType
• [x] Add testcases
• [x] Refactor relevant functions
• [x] Resolve in-line todo list
• [x] Update docs and spec

References

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