Add support for more generic CBVs by way of a generic router

[dmontagu]

Addresses #2

[codecov]

Codecov Report

Merging #3 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master     #3   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           9      9           
  Lines         288    317   +29     
  Branches       35     38    +3     
=====================================
+ Hits          288    317   +29

Impacted Files	Coverage Δ
fastapi_utils/cbv.py	100% <100%> (ø)	⬆️

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