Many things need to be moved to a plugin

_From @theoreticalbts on October 30, 2015 19:42_

Things in core that need to move to plugins:

Indexes:
- `account_member_index`

Objects:
- `impl_account_transaction_history_object_type`
- `impl_witness_schedule_object_type`
- `impl_budget_record_object_type`
- remove `impl_reserved0_object_type`
- remove `custom_object_type`
- `operation_history_object_type`

Fields:
- `account_object.whitelisted_accounts`
- `account_object.blacklisted_accounts`
- `witness_object.last_aslot`
- `witness_object.url`
- `witness_object.total_missed`
- `witness_object.last_confirmed_block_num`
- `dpo.recent_slots_filled`
- `dpo.last_irreversible_block_num`
- `dpo.recently_missed_count`

_Copied from original issue: cryptonomex/graphene#422_

Start by mapping the listed indexes, object types, and fields to their definitions in the core code, then read the existing plugin architecture and related migration patterns. The issue is complete only when each listed item is moved or removed as specified without breaking builds, persistence, or behavior, but it does not name files or tests to guide that work.

Written by the indexing model from the issue text.