Add support for parsing and analysing negative values

[tarunbhm]

Summary by CodeRabbit

• New Features

  • Introduced support for handling negative numbers in formula parsing and analysis.
  • Added a new public function to initialize FormulaConfig with specific parameters.

• Bug Fixes

  • Improved the handling and simplification of arithmetic expressions involving negative numbers.

• Documentation

  • Clarified the purpose of the formula field in the README.

• Tests

  • Added multiple tests to validate scenarios of multiplication, division, exponentiation, and negation operations.

• Enhancements

  • Updated the parser and analyzer to better handle and simplify expressions with negative values.
  • Enhanced the LaTeX generator to format negative expressions correctly.