Provide a way to specify the start up agent on the command line

[DJackman123]

Summary of the new feature / enhancement

When I start aish.exe, it prompts me to choose an agent to use. For an interactive session this isn't a big deal, but for a single query on the command line, it's a pain to have to choose this every time. Please add a command line parameter for specifying which agent to use so I don't get prompted.

Proposed technical implementation details (optional)

No response

[StevenBucher98]

We should definitely include an optional parameter --agent or -a that would allow users to select an agent

[daxian-dbw]

The active agent should be configured in the configuration file of AISH, but today we haven't yet implemented the configuration support.

[StevenBucher98]

We will use this issue to track a non-interactive way to call aish and open a new issue to track the configuration file for default agent to use