feat: Add connections field to IOKey and remove Connect object

[kberat-synnada]

Description

Closes #93.

What is Changed

• "connections" argument and attribute added to IOKey.
• Connect object is removed.
• Corresponding tests are updated.

Checklist:

• Tests that cover the code added.
• Corresponding changes documented.
• All tests passed.
• The code linted and styled (pre-commit run --all-files has passed).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.58%. Comparing base (d65f1e7) to head (fce6951).
Report is 1 commits behind head on main.

@@           Coverage Diff           @@
##             main      #94   +/-   ##
=======================================
  Coverage   86.57%   86.58%           
=======================================
  Files          61       61           
  Lines       15587    15575   -12     
=======================================
- Hits        13494    13485    -9     
+ Misses       2093     2090    -3     

Files with missing lines	Coverage Δ
mithril/__init__.py	80.70% <100.00%> (ø)
mithril/framework/common.py	96.50% <100.00%> (-0.01%)	⬇️
mithril/framework/logical/base.py	88.04% <100.00%> (-0.16%)	⬇️
mithril/framework/logical/model.py	97.11% <100.00%> (+0.33%)	⬆️
mithril/utils/dict_conversions.py	88.85% <100.00%> (+0.03%)	⬆️

... and 1 file with indirect coverage changes

[aturker-synnada]

LGTM!