feat(@schematics/angular): hide universal schematic
feat(@schematics/angular): hide universal schematic

The universal schematic by itself doesn't get you a working server application.

BREAKING CHANGE: universal schematic is now hidden and cannot be used with the `ng generate` command.

Users who want a working universal application should use `ng add @nguniversal/express-engine` or `ng add @nguniversal/hapi-engine`

Closes: #15166

geofffilippi/angular-cli,ocombe/angular-cli,ocombe/angular-cli,geofffilippi/angular-cli,clydin/angular-cli,Brocco/angular-cli,clydin/angular-cli,DevIntent/angular-cli,hansl/angular-cli,DevIntent/angular-cli,catull/angular-cli,manekinekko/angular-cli,geofffilippi/angular-cli,angular/angular-cli,filipesilva/angular-cli,angular/angular-cli,catull/angular-cli,hansl/angular-cli,hansl/angular-cli,hansl/angular-cli,catull/angular-cli,beeman/angular-cli,DevIntent/angular-cli,ocombe/angular-cli,angular/angular-cli,beeman/angular-cli,filipesilva/angular-cli,ocombe/angular-cli,manekinekko/angular-cli,catull/angular-cli,Brocco/angular-cli,geofffilippi/angular-cli,Brocco/angular-cli,clydin/angular-cli,angular/angular-cli,beeman/angular-cli,filipesilva/angular-cli,Brocco/angular-cli,Brocco/angular-cli,DevIntent/angular-cli,beeman/angular-cli,DevIntent/angular-cli,manekinekko/angular-cli,ocombe/angular-cli,filipesilva/angular-cli,clydin/angular-cli