Replace old markdown and remove redundant events (#389)

* Remove redundant messages

* Replaced old markdown with preview.
Added nuget config to add preview feed

* Fix old extensions usage

* Scrollbar margin for the markdown.

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Co-authored-by: Burak Kaan Köse <bkaankose@outlook.com>

.gitignore

@@ -206,9 +206,6 @@ PublishScripts/
 *.nuget.props
 *.nuget.targets
 
-# Nuget personal access tokens and Credentials
-nuget.config
-
 # Microsoft Azure Build Output
 csx/
 *.build.csdef