Lesson 6 - Observability - Aspire dashboard

[yortch]

Add new lesson that shows how to add .NET Aspire Dashboard for observability:
Acceptance criteria:

• lesson and solution files are created
• lesson mkdocs files are added
• .NET aspire is added to deployable app
  https://learn.microsoft.com/en-us/semantic-kernel/concepts/enterprise-readiness/observability/telemetry-with-aspire-dashboard