Add instance variable annotations for SES models

[giograno]

This PR reworks the annotation for SES, as suggested in https://github.com/getmoto/moto/issues/9389.

In a few instances, a proper type annotation would require the introduction of new types mapping specific AWS data types. A case would be having a type for dkim_attributes that implements the proper AWS type (DkimAttributes). Instead of introducing a new type, I left a generic typing.Any.

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 93.00%. Comparing base (c75db89) to head (7edd158).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9387   +/-   ##
=======================================
  Coverage   93.00%   93.00%           
=======================================
  Files        1294     1294           
  Lines      115774   115853   +79     
=======================================
+ Hits       107670   107750   +80     
+ Misses       8104     8103    -1     

Flag	Coverage Δ
servertests	28.75% <88.57%> (+0.04%)	:arrow_up:
unittests	92.98% <100.00%> (+<0.01%)	:arrow_up:

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