Improve package setup and structure

[mano8]

changes:

• Improve code style
• Improve package setup
• Improve requirements files
• improve Utils structure inheritance

[mano8]

ok

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ
emon_tools/__init__.py	100.00% <100.00%> (ø)
emon_tools/api_utils.py	100.00% <100.00%> (ø)
emon_tools/fina_utils.py	88.52% <100.00%> (-6.55%)	⬇️
emon_tools/utils.py	100.00% <100.00%> (ø)