Add .Net Auto-instrumentation Developer Documentation

[jvoravong]

Description:

• Add support developer documentation for Splunk .Net auto-instrumentation in Kubernetes.
• The mentioned .NET demo will be added in a follow up PR.
• Adding tests in a follow up PR to keep the PR diff low.

Testing:

• Adding functional tests in a follow up PR.

Documentation:

• Added documentation for how to use .Net auto-instrumentation. Customer documentation has been created based off of initial changes and feedback.

[atoulme]

looks like a great start!

[jvoravong]

This PR was originally going to add documentation, a demo application, and functional testing. However, do to scope of work increasing, I'm splitting up this work. I'm only adding documentation in this PR. The demo application and functional tests will be added in separate followup PRs.