Char encode and decode rework

[RonanB96]

This pull request updates the documentation and usage patterns for Bluetooth GATT characteristic value parsing, standardizing the method naming and clarifying the recommended APIs. The most significant changes are the switch from decode_value to parse_value for public APIs, the renaming of internal implementation methods to _decode_value, and improvements to documentation and examples in both the README and instruction files.

API and Method Naming Standardization:

• Changed all public-facing documentation and examples to use parse_value instead of decode_value for parsing characteristic values, ensuring consistency and clarity in the recommended API. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
• Updated all internal implementation examples and instructions to use _decode_value for private/protected characteristic parsing logic, reflecting the intended encapsulation and usage patterns. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]

Documentation and Example Improvements:

• Overhauled the README.md to clarify the distinction between type-safe characteristic class usage and dynamic parsing via UUID strings, with new code examples and clearer recommendations for both approaches. [1] [2]
• Enhanced instructional markdown files to reflect the new method names and provide up-to-date, consistent usage patterns for both implementation and testing. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

Testing and Validation:

• Updated all test instructions to use parse_value, ensuring that tests align with the new public API and reinforcing the intended usage for developers. [1] [2] [3] [4] [5] [6] [7] [8]

These changes collectively improve the clarity, consistency, and usability of the Bluetooth GATT characteristic parsing APIs and documentation.