Standardize wallet RPC names with new aliases

[zhyatt]

Where indicated in the following table, a new alias for the wallet RPC commands should be created and the previous RPC command name deprecated. This will standardize the names for wallet-specific RPC calls to make them more recognizable. Notes are included for areas with open questions and where related activities are covered in other issues.

Current RPC name	New RPC name	Notes
account_create	wallet_account_create
account_list	wallet_account_list
account_move	wallet_account_move
account_remove	wallet_account_remove
account_representative_set	wallet_account_representative_set
accounts_create	wallet_accounts_create
password_change	TBD	See #3756
password_enter	TBD	See #3756
password_valid	TBD	See #3756
wallet_key_valid	TBD	See #3756
receive	wallet_receive
receive_minimum	wallet_receive_minimum
receive_minimum_set	wallet_receive_minimum_set	Is this persisted in the wallet database and overwrite the related config?
search_pending	wallet_search_receivable	See #3689
search_pending_all	wallet_search_receivable_all	See #3689
send	wallet_send
wallet_add	wallet_add_key	This seems more appropriate of a name
wallet_add_watch	No change
wallet_pending	wallet_receivable	See #3689
work_get	wallet_work_get
wallet_work_get	wallet_work_get_all	To match other _all covering calls and avoid singular and plural _account_* being needed
work_set	wallet_work_set
wallet_balances	No change
wallet_change_seed	No change
wallet_contains	No change
wallet_create	No change
wallet_destroy	No change
wallet_export	No change
wallet_frontiers	No change
wallet_history	No change
wallet_info	No change
wallet_ledger	No change
wallet_lock	No change	Related #3758 and #3756
wallet_locked	No change
wallet_representative	No change
wallet_representative_set	No change
wallet_republish	No change