Documentation and Code refactor

[eadwinCode]

What's new

• Added documentation
• Drop file and image fields for Sqlalchemy-file
• Merged create_all_async, drop_all_async and reflect_all_async to create_all, drop_all and reflect_all respectively.

[codecov]

Codecov Report

Attention: 14 lines in your changes are missing coverage. Please review.

Comparison is base (cc5c5af) 94.70% compared to head (ff04943) 93.80%.
Report is 2 commits behind head on master.

Files	Patch %	Lines
ellar_sql/module.py	88.23%	4 Missing ⚠️
ellar_sql/factory/base.py	95.23%	3 Missing ⚠️
ellar_sql/schemas.py	78.57%	3 Missing ⚠️
ellar_sql/model/base.py	85.71%	2 Missing ⚠️
ellar_sql/migrations/multiple.py	80.00%	1 Missing ⚠️
ellar_sql/migrations/single.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #10      +/-   ##
==========================================
- Coverage   94.70%   93.80%   -0.91%     
==========================================
  Files          42       35       -7     
  Lines        1644     1517     -127     
==========================================
- Hits         1557     1423     -134     
- Misses         87       94       +7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.