python packages renaming -- sample updates

[axelsrz]

This pull request introduces a breaking change to the Python import structure for the Microsoft Agents SDK samples, switching all imports from the dotted microsoft.agents format to the underscored microsoft_agents format. The change affects all sample projects, documentation, and logging configuration, and requires updating your code and logger namespaces accordingly.

Breaking change: Python import structure

• All SDK imports have been updated from microsoft.agents to microsoft_agents across every sample source file, including modules for activity, hosting, authentication, storage, and Copilot Studio client. [1] [2] [3] [4] [5]
• The logging configuration in all samples now uses the microsoft_agents namespace instead of microsoft.agents, and documentation has been updated to reflect this change. [1] [2] [3] [4] [5] [6] [7] [8]

Documentation updates

• Added an "Important Notice" section to samples/python/README.md explaining the breaking import change and providing updated import examples for all major modules.
• Updated references in documentation to use the new microsoft_agents import path, including links and code snippets. [1] [2]

Sample code consistency

• All sample code files now consistently use the new import format, ensuring compatibility and reducing confusion for developers. [1] [2] [3] [4] [5] [6]

Server and adapter initialization

• All server startup scripts and adapter initializations have been updated to use the new import paths for agent application, authentication, and hosting modules. [1] [2] [3]

Please ensure you update your codebase and any custom scripts to use microsoft_agents for all imports and logger configurations.