clean up imports a bit

[bendichter]

• stay away from private modules
• use Type when indicating that an arg should be a class

Motivation

What was the reasoning behind this change? Please explain the changes briefly.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.16%. Comparing base (910ceba) to head (14e7029).
Report is 3 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #498      +/-   ##
==========================================
+ Coverage   82.06%   82.16%   +0.10%     
==========================================
  Files          47       47              
  Lines        1355     1357       +2     
==========================================
+ Hits         1112     1115       +3     
+ Misses        243      242       -1     

Flag	Coverage Δ
unittests	82.16% <100.00%> (+0.10%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/nwbinspector/_configuration.py	96.22% <100.00%> (ø)
src/nwbinspector/_formatting.py	87.59% <100.00%> (+0.18%)	⬆️
src/nwbinspector/_inspection.py	83.08% <100.00%> (ø)

... and 1 file with indirect coverage changes