w/ current ACL implementation, these roles will not work for us. ACL
limits only 1 set of params for a given (_who, _entity, _role), but a
single address may control multiple PledgeAdmins.
By placing all state variables in 1 place, this allows us to add
additional state at a later date, and not overwrite an existing
state variable.
Also optimized struct layout to better pack
perissology