Updated the Mandatory Parameters and Initialization Logic

[MinuraPunchihewa]

This PR makes the following improvements:

• Makes the name parameter mandatory for both data sources and Minds to avoid creating random names each time either of them are initialized.
• Allows re-use of existing data sources and Minds by providing only the name.
• Moves the initialization logic for data sources to AIMindDataSource for improved modularity.
• Enables credentials for data sources to be configured via environment variables using the AIMindEnvVar class.
• Improves the docstrings for the classes and their methods.

The documentation and tests are yet to be updated based on these changes.

[StpMax]

description is not mandatory for datasource creation

[MinuraPunchihewa]

You're right, I can see that here, but it's marked as required in our docs and in our front-end as well, I believe.

I will fix the docs.