An internal schematics helper rule has been introduced for Angular schematics that only generate a set of project files from a set of templated files. Multiple current generation schematics contained essentially the same code which increased the sustainment burden and made refactoring and improvements more complicated.
Currently, if the user hits `<Enter>` before selecting an interface to implement, the CLI generates a broken guard that implements no interface. With this commit, the CLI forces a choice in interactive mode and generates a `CanActivate` guard by default.
Currently when using `ivy-ngcc` it will print out a warning
```
Failed to read entry point info from //node_modules/@schematics/angular/workspace/files/package.json with error SyntaxError: Unexpected token < in JSON at position 1121.
```
Fixes#13378
This aligns options that do the same thing:
1) `skipSpecs` and `spec` has been deprecated in favor of `skipTests`.
2) `styleext` has been deprecated in favor of `style` since the latest is two words.
Fixes#12784
