Add PrivateEndpointConnection Swagger (#6727)

* Add PrivateEndpointConnection Swagger

* Adding examples

* Fix to pass validation

* PrivateLinkResources

* Accidentally put PrivateLinkResourceGet.json in wrong place

* Add PEC files to readme

* add new swagger files to package-composite-v3

* update PrivateLinkResource swagger file

* Added incorrect PrivateLinkResource swagger file

* fix lintdiff validation errors

* remove PrivateLinkResources from this PR

* forgot to update example

* Update PEC swagger for BO

* address Anthony's comments