Add SiteExtension.proj to replace build-extension.ps1 (#10168)
* Add SiteExtension.proj
* Publish workers, hash hard links
* Add workers.props, avoid publishing worker files
* Refactor how worker is packaged
* Add PrivateSiteExtension
* Fix duplicate build and file write error
* Comment and split out powershell regex match
* Fix MoveSymbols
* Publish PrivateSiteExtension
* Remove Python worker from private extension
* Zip site extension artifacts
* Clean dotnet worker files
* Default ZipArtifactsPath to PackageOutputPath
* Add comments, update dotnet sdk
* Add explicit CI restore stage
* Split out build stage as well
* Add python.props back in with redirection message
* Fix integration build issue
* Fix symbols output
* Revert python.props changes
* Revert global.json change
* Extract build site extension into template
* Remove build-extension.ps1
* Add build-extensions.ps1 back, with error directing to replacement
* Fix log publishing
* Fix check-vuln placement
* Fix deletion of code-sign summary files
* Fix symbol SBOM and artifact
* Add single/multi-tfm support for SiteExtension.proj
* Fix end-of-file line breaks
* Extract Workers to their own props files
* Fix ZipPublish when zip not specified
* Remove redundant python removal
* .proj -> .csproj
* Remove minorVersionPrefix
* Update CODEOWNERS
* Add EnsureWorkersFolder target
* Fix windows build
* Pack linux artifact
* Add release config
* Fix nuget signing path
* Add condition for hard link hashes
* Add IsZippable check and readme