* copy umbraco-package-schema.json over from the New.Client build
* when a project referencing Cms.Targets is building, we want to copy out the umbraco-package-schema.json file to the project directory if it does not exist
* ignore built output files
* fix typo
* add PackageReference to Umbraco.Cms.Targets to ensure dependent json schema files are copied over
* add to gitignore
* add target to remove the _UmbracoCmsPackageSchemaReference on clean
* Revert "add PackageReference to Umbraco.Cms.Targets to ensure dependent json schema files are copied over"
This reverts commit 339043a36fd0074624c3060ff0113283a9eb6376.
* generate umbraco-package-schema.json on demand in Cms.Targets
* add generated file to .gitignore