feat: base 64 formulas support

[arzola]

This pull request includes several improvements and new features to the codebase, particularly focusing on enhanced handling of LaTeX and AsciiMath formulas, including support for base64 encoded formulas, and updates to dependencies and tests. The most important changes are outlined below:

Dependency Updates:

• Updated chai to version 4.5.0 and mocha to version 10.8.2. Added new dependencies: proxyquire and sinon. (package.json)

Feature Enhancements:

• Enhanced routes/latex.js to handle base64 encoded formulas and added validation for formula and color format. (routes/latex.js)
• Improved imageGenerator.js to decode HTML entities, handle base64 encoded formulas, and validate SVG content before generating PNGs. (src/imageGenerator.js) [1] [2]

Testing Improvements:

• Refactored asciimath.test.js to use mock responses and added tests for various scenarios including complex expressions and error handling. (test/asciimath.test.js)
• Added new test file base64.test.js to cover base64 encoded formulas for TeX, AsciiMath, and MathML formats, including edge cases. (test/base64.test.js)

Minor Changes:

• Modified the home page title in routes/index.js to include an emoji for a more engaging UI. (routes/index.js)
• Removed redundant comments and console logs for cleaner code in imageGenerator.js. (src/imageGenerator.js) [1] [2]

[arzola]

I need to fix a remaining issue with asciimath hold a little bit

[ho-man-chan]

LGTM