[Persistence] Consolidate common behaviour between `Pool` and `Account` into a shared interface

[Olshansk]

Objective

Remove redundant code used by the Pool and Account actors in the persistence module introduced in https://github.com/pokt-network/pocket/pull/73.

This is a good starter task opportunity to get acquainted with the codebase in the persistence module.

Origin Document

From the utility specification, a Pool is described as:

    A ModulePool is a particular type that though similar in structure to an Account, the
    functionality of each is quite specialized to its use case. These pools are maintained by
    the protocol and are completely autonomous, owned by no actor on the network. Unlike Accounts,
    tokens are able to be directly minted to and burned from ModulePools. Examples of ModuleAccounts
    include StakingPools and the FeeCollector

Similar to how the functionality of Fisherman, ServiceNode, Validator and Application was consolidated via persistence/schema/protocol_actor.go and persistence/schema/base_actor.go, the functionality of Pool and Account can also be shared to remove redundant code.

Goals

Deliverables

• [ ] Extract common functionality of Pool and Account into a common interface
• [ ] At a minimum, the following files will need to be affected: persistence/schema/account.go, persistence/account.go, persistence/test/account_test.go

Testing Methodology

• [ ] $ make test_persistence
• [ ] $ make test_all
• [ ] Run a LocalNet following the instructions in docs/development/README.md

Non-goals

• Adding new functionality to the persistence module

Creator: @Olshansk Owner: @DragonDmoney Co-Owners: @andrewnguyen22

[DragonDmoney]

Note: I am currently working on this.

[Olshansk]

+1 Updated you as an owner in the description changed this to in progress

[Olshansk]

@DragonDmoney Do you think this is something you can have up for review by the end of the month?

[andrewnguyen22]

Somewhat tackled in #154 by merging the two structures in protobuf. Will leave the rest to #163

[Olshansk]

Spoke to @DragonDmoney offline and he mentioned he won't be working on this any longer.

[h5law]

@Olshansk I would like to take a swing at this issue if its still relevant? I have working code that passes tests ready to submit a PR if its still applicable?

[Olshansk]

@Olshansk I would like to take a swing at this issue if its still relevant? I have working code that passes tests ready to submit a PR if its still applicable?

Still applicable, let's do it!