feat/improve configuration

[onerandomusername]

• feat: rewrite the entire configuration system to use marshmallow and attrs
• config: remove config_default.toml since its now part of the classes

Closes #22

[codecov[bot]]

Codecov Report

Merging #75 (f0ec067) into main (4b07917) will decrease coverage by 3.08%. The diff coverage is 61.79%.

:exclamation: Current head f0ec067 differs from pull request most recent head 4644d76. Consider uploading reports for the commit 4644d76 to get more accurate results

@@            Coverage Diff             @@
##             main      #75      +/-   ##
==========================================
- Coverage   70.90%   67.81%   -3.09%     
==========================================
  Files          33       35       +2     
  Lines        1619     2082     +463     
  Branches      199      286      +87     
==========================================
+ Hits         1148     1412     +264     
- Misses        439      610     +171     
- Partials       32       60      +28     

Impacted Files	Coverage Δ
modmail/__main__.py	0.00% <0.00%> (ø)
modmail/extensions/meta.py	73.91% <ø> (ø)
modmail/extensions/extension_manager.py	35.15% <22.22%> (+0.79%)	:arrow_up:
modmail/extensions/configuration_manager.py	38.60% <38.60%> (ø)
modmail/bot.py	38.28% <50.00%> (-0.57%)	:arrow_down:
tests/modmail/conftest.py	75.00% <57.14%> (-11.96%)	:arrow_down:
modmail/config.py	67.13% <66.66%> (-29.79%)	:arrow_down:
tests/modmail/test_config.py	95.94% <95.94%> (ø)
modmail/__init__.py	100.00% <100.00%> (ø)
modmail/utils/embeds.py	81.08% <100.00%> (-0.50%)	:arrow_down:
... and 1 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update d47e097...4644d76. Read the comment docs.

[onerandomusername]

This pr is now feature frozen, a full system to be able to change settings while the bot is running will be added later, the rudimentary system provided here is good enough for now.

[coveralls]

Coverage decreased (-2.8%) to 75.0% when pulling 4644d760c5f185ee8899534f9214d91aca6ab365 on feat/improve-configuration into d47e09784d6c9c063ec4083a1a4f40ecb275bdab on main.