Initial implementation of generators feature

[rszamszur]

Checklist:

• Added tests for changed code where applicable.
• Documentation reflects the changes where applicable.
• Updated the CHANGELOG.md file with your changes.
• My PR is ready to review.

Resolves: #69
Resolves: #68
Resolves: #47
Resolves: #71
Resolves: #72
Resolves: #73

Description of the changes being introduced by the pull request:

TODO:

• Implement base abstract class for all generators to inherit
• Solve the problem of dynamically creating click sub-commands at runtime - add initial implementation.
• Implement method for programmatically loading user generated generators from path at runtime
• Solve the problem of dynamically creating click sub-commands arguments and options at runtime based on chosen generators - add initial implementation
• Implement controller generator with template
• Implement generator generator with template
• Refactor invoker with using deque
• Refactor fastapi_mvc.commands to be more generic
• Implement global except hook, refactor current project exceptions
• Add and modify unit test cases
• Add docstrings
• Fix styleguide
• Add integration tests for builtins generators -> will be done via Add integration tests for fastapi-mvc generators #76
• Add integration tests for programmatically loading user generators

This will be a looooong merge 🚀

[github-actions]

🚀 Deployed on https://6262faea5eb68b0254151a6c--fastapi-mvc.netlify.app

[rszamszur]

To not make this merge much more extensive, documentation will be added via separate PR

Related issues:
#74
#75

[codecov-commenter]

Codecov Report

Merging #70 (8b5a987) into master (ffb5cf3) will increase coverage by 0.14%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #70      +/-   ##
==========================================
+ Coverage   99.49%   99.63%   +0.14%     
==========================================
  Files          34       39       +5     
  Lines         591      817     +226     
==========================================
+ Hits          588      814     +226     
  Misses          3        3              

Impacted Files	Coverage Δ
fastapi_mvc/__init__.py	100.00% <100.00%> (ø)
fastapi_mvc/borg.py	100.00% <100.00%> (ø)
fastapi_mvc/cli/cli.py	100.00% <100.00%> (ø)
fastapi_mvc/cli/generate.py	100.00% <100.00%> (ø)
fastapi_mvc/cli/new.py	100.00% <100.00%> (ø)
fastapi_mvc/cli/run.py	100.00% <100.00%> (ø)
fastapi_mvc/commands/__init__.py	100.00% <100.00%> (ø)
fastapi_mvc/commands/generate.py	100.00% <100.00%> (ø)
fastapi_mvc/commands/invoker.py	100.00% <100.00%> (ø)
fastapi_mvc/commands/run_shell.py	100.00% <100.00%> (ø)
... and 12 more

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