.Net: DRAFT - ADR for Agent Architecture

[crickman]

Motivation and Context

Outline one approach for agent-filters.

Description

All of the regular Kernel filters are utilized as part of Agent Framework.
The agent-filter provides the ability to intercept, examine, and optionally suppress an agent response within the context of any AgentChat.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄