[IMPROVEMENT] Modularize recon-pipeline.py's ReconShell class

[epi052]

Is your feature request related to a problem? Please describe. The ReconShell class's monolithic design has grown to nearly 1000 lines of code. Making changes to it can be daunting and things that need to be changed can be hard to locate.

Describe the solution you'd like The cmd2 team added a feature in 1.3.0 called CommandSets that allow for modularization of cmd2 applications. This seems like a perfect fit.

Describe alternatives you've considered I've considered rolling my own modular structure using a MetaClass, as I've been successful with this strategy in the past, however with it being a builtin feature of cmd2, it feels too good to pass up.