Save ReadLine history files to .aish config folder

[StevenBucher98]

Summary of the new feature / enhancement

If I am switching between different agents, my history predictions may be relevant to one agent but irrelevant to another.

Proposed technical implementation details (optional)

It may make sense to split out the ReadLine history to be per agent and then the files to be within the agents folder within .aish.

[daxian-dbw]

History queries are not strictly applied to only 1 particular agent. For example, the queries I used for az-cli and az-ps agents are also appliable to the openai-gpt agent, and I do send same queries to them quite often to compare the results in my workflow.

But I agree that the history file should be save to the AI Shell's config folder.