accounts/abi: Types redo

[VoR0220]

• this includes an intermediate better slice/array scheme (there's a better one in the next PR which will be coming in the next few hours)
• this includes a redone type schema where most of the type is handled by reflection and the typebyte, and consequently, resolves to the reflect.Type of its kind at all points (see type tests if this statement is confusing and correct me please).
• includes vigorous testing of the types and eliminates the ability to specifiy "uint" or "int" because that is incorrect and should evaluate to the full size in the abi (ie it's the compilers job to make sure it evaluates fully to uint256 or int256)
• Can now create fully recursive slices/arrays of any type available in the ABI.

[fjl]

This is contained in #14743