Add EchoBot dotnet Sample

[rido-min]

No description provided.

[tracyboehrer]

This shouldn't be here. We should add appsettings.Development and appsetting.Production to .gitignore

[rido-min]

appSettings.Development can be used to share settings across a team, hence it's not gitignored. And more importantly it will be included in the packaged app for deployment. What is a bad security practice.

[tracyboehrer]

My only issue with this is Matt wants to push the DotNet Application merge early next week, and that will then be a new sample. So this work will be short lived.

[rido-min]

My only issue with this is Matt wants to push the DotNet Application merge early next week, and that will then be a new sample. So this work will be short lived.

same as with docs. Once we have the application object we will update it MyBot.cs. The main point of this PR is not the sample itself, rather the infra: CI, Feeds, CodeSpaces, alignment across languages, etc..

[rido-min]

not sure if having 2 CI is the right thing (we could also add some path filters), or just build ALL samples across languages in a single GHAction.

[tracyboehrer]

Closing due to AgentApplication version of this sample having been merged instead. Thanks for the effort though.