refactor: set senior stock cache ttl from settings

[br-monteiro]

This pull request introduces configurable cache TTL (time-to-live) settings for authentication tokens and stock data in the Senior Stock API integration. It allows users to adjust how long authentication tokens and stock data are cached, either through configuration files or environment variables, and updates the documentation accordingly.

Configuration and documentation updates:

• Added cache_token_ttl_seconds and cache_data_ttl_seconds as optional settings in the configuration example in README.md, and documented their purpose and default values. [1] [2]
• Updated the environment variable section in README.md to include ONECLI_CACHE_TOKEN_TTL_SECONDS and ONECLI_CACHE_DATA_TTL_SECONDS.

Implementation of configurable cache TTLs:

• Updated the SeniorStockAPI class in senior_stock_api.py to read cache_token_ttl_seconds and cache_data_ttl_seconds from settings, falling back to default constants if not provided.
• Modified token and data caching logic to use the configurable TTL values instead of hardcoded constants. [1] [2]