Make module names consistent and remove redundant module casting

[sdb9696]

Addresses the inconsistent naming of smart modules by removing all "Module" suffixes and aligning filenames with class names. Removes the casting of modules to the correct module type now that is is redundant due to #895. Also updates the adding of iot modules to use the ModuleNames rather than a free string.

[codecov]

Codecov Report

Attention: Patch coverage is 97.58065% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 90.58%. Comparing base (9473d97) to head (85da998).

Files	Patch %	Lines
kasa/smart/smartdevice.py	92.30%	1 Missing and 1 partial ⚠️
kasa/iot/iotdevice.py	92.30%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #909   +/-   ##
=======================================
  Coverage   90.57%   90.58%           
=======================================
  Files          75       75           
  Lines        5093     5096    +3     
  Branches     1246     1246           
=======================================
+ Hits         4613     4616    +3     
  Misses        391      391           
  Partials       89       89           

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[rytilahti]

LGTM, thanks for cleaning this up! Just a minor note that might be worth reconsideration, but other than that this looks good to go for me.