Summarize plan preveiw with gen ai?

[kentakozuka]

Generative AI can provide a summary and more insights of plan-preview.
WDYT?

[t-kikuc]

I think we should not (and don't want to) maintain GenAI components because it'd be troublesome although the feature seems useful.
This feature should be released as an external util, not pipecd's official one.

WDYT guys?