RFC: Schematics: Extend from @schematics/angular

[MichaelWarneke]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[x] Feature request
[ ] Documentation issue or request

What is the current behavior?

Some individual angular cli schematic generators are are listed in the collection.json.
This list has to be kept updated.

Expected behavior:

Extend the ngrx schematics from @schematics/angular and not the individual generators.

Version of affected browser(s),operating system(s), npm, node and ngrx:

@ngrx/schematics 5.1.0

Other information:

The angular devkit has been updated to allow extends.
angular/devkit#34
I created a local branch with required changes and can pull if requested.
Changes:

• Updated Angular CLI to 1.7.2 (for the new "extends" scheme element)
• Removed class, component, directive, enum, guard, interface, module, pipe and service from the collection.json
• Added "extends": ["@schematics/angular"] to the collection.json
• Implemented a test to check if ngrx schematics runs the extended angular schematics generator ( g class)

[brandonroberts]

Fixed via 0e17aad