Refactor Python palindrome checker functions

[joaopedrocampos]

Fixes issue: Improves the palindrome Python script since it was outdated and not following basic PEP rules like functions naming conventions

Changes:

• Updated the function is_palindrome_recursive to handle strings of length 1 or less.
• Simplified the logic in the function is_palindrome_reverse by using string slicing.
• Optimized the function is_palindrome_iterative by removing unnecessary lines of code.