Add support for Fortran complex numeric types

[billschereriii]

Description

Fortran has built-in support for complex numeric types, and these are used in some simulations. We should plumb support for these through SmartRedis.

Justification

Fortran users who do simulations with complex types will benefit

Implementation Strategy

Paralleling existing numeric types should get us most of the way there once we figure out the in-memory representation of the complex types. There may need to be some back-end support to handle them if the data types are larger than what is supported today.