Create a separate Nuget hosting just managed assemblies (#3020) (#3106)
* Initial commit
* More changes
* More changes
* More changes 3
* More changes 4
* More changes 5
* More changes 5
* More changes 6
* More changes 7
* More changes 8
* Remove C# ifdefs
* More changes 10
* More changes 11
* YAML changes for other release pipelines
* Add release notes metadata
* Props and Targets change
* Add CSHarp proj
* More changes 12
* More changes
* Minor fix
* Minor fix
* Fix yaml
* Some missing logic for winml
* Minor update
* Fix casing for winmd file
* Fix casing
* Add targets and props for managed section into native nuget
* revert file
* a