feature(agent): Knowledge add retriever name&desc getter and stter

[cinjoseph]

Description

Add the ability to retrieve the retriever's name and description in Knowledge, so that prompts referencing this knowledge can be more enriched.

How Has This Been Tested?

test by myself, config knowledge on dbgpt web and test whit a conversation to the agent

Snapshots:

Include snapshots for easier review.

Checklist:

• [ * ] My code follows the style guidelines of this project
• [ * ] ] I have already rebased the commits and make the commit message conform to the project standard.
• [ * ]] I have performed a self-review of my own code
• [ * ]] I have commented my code, particularly in hard-to-understand areas
• [ * ] ] I have made corresponding changes to the documentation
• [ * ] ] Any dependent changes have been merged and published in downstream modules

[cinjoseph]

@fangyinc

[Aries-ckt]

r+

[csunny]

r+