Refactor Generator class

[elmkarami]

What's this PR do?

Split the main Generator class into multiple independent generator
classes

Any background context you want to provide?

Will make it easy to add new functionality to the generator or add new generator classes + independently testable

Definition of Done (check if considered and/or addressed):

• Are all backwards incompatible changes documented in this PR?
• Have all new dependencies been documented in this PR?
• Has the appropriate documentation been updated (if applicable)?
• Have you written tests to prove this change works (if applicable)?

[Abdenasser]

@elmkarami awesome 👍🏻 , please rebase and make test if there is any linting errors make format

[codecov]

Codecov Report

Merging #19 (840e156) into main (c84cd83) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main       #19   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           10        10           
  Lines          240       255   +15     
=========================================
+ Hits           240       255   +15     

Impacted Files	Coverage Δ
dr_scaffold/generators.py	100.00% <100.00%> (ø)

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[Abdenasser]

Amazing @elmkarami, I really appreciate the time you put on this ... thanks a lot buddy 🥇