[FEATURE]: Add timeout to prevent long-running functions (Closes #658)

[AdwitaSingh1711]

Summary:
Implements a 30-second warning and 300-second abort function mechanism as default for functions in src/execution/evaluator.rs. It also allows per-function overriding by specifying a timeout in decorator arguments, similar to the caching method.

Fixes #658

Examples:

1. In examples/manuals_llm_extraction/main.py we can add @cocoindex.op.executor_class(timeout=15) to override current 300second timeout as shown

2. Additionally, if any other function takes longer than 30 seconds to execute, a warning message is displayed. If the execution time exceeds 300 seconds, the function times out.

Checklist:

• I have run all tests and pre-commit checks, which have passed.
• Cache, logs and others are not accidentally added to git's tracking history.
• My commits follow the conventional commits format.