feat(components): add checkbox component

[desmondinho]

Description

Add the checkbox component to the library of components.

Closes #20

What's been done?

Added the checkbox and base input components with the following abilities:

Base input

• Set the disabled state
• Set the read-only state
• Set the theme color (e.g., primary, danger)
• Set the border radius (e.g., none, medium)
• Set the size (e.g., small, large)
• 2-way value binding

Checkbox

• Set custom label content
• Set custom check icon
• Set CSS class names for each slot

Checklist

• My code follows the project's coding style and guidelines.
• I have included inline docs for my changes, where applicable.
• I have added, updated or removed tests according to my changes.
• All tests are passing.
• There's an open issue for the PR that I am making.

Additional Notes

[codecov]

Codecov Report

Attention: Patch coverage is 98.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 98.11%. Comparing base (f1a6b43) to head (f9251fb).
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/LumexUI/Components/Bases/LumexInputBase.cs	97.37%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #21      +/-   ##
==========================================
+ Coverage   98.06%   98.11%   +0.05%     
==========================================
  Files          33       37       +4     
  Lines         823      898      +75     
  Branches       78       89      +11     
==========================================
+ Hits          807      881      +74     
  Misses         12       12              
- Partials        4        5       +1     

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