feat(domain,feature): add property to specify build type

[pascalbe-dev]

I was having issues with a few things, when working with the repo:

• When pulling the latest version from npm, I received code which had the publishable flag always being set to true when creating angular libs via the nrwl angular library schematic. I could, however, not find that in the current master branch of the repo. Is the repo out of sync with the npm deployment?
• Testing the schematics locally (via e2e testing or directly via the CLI) did not work out of the box for me. Is the setup a bit broken or did I miss something? I'd be happy to help out, if there are some problems with the setup.

Currently, the buildable flag is not yet supported in the latest nx release (see this issue), so setting the type to "buildable" would create a lib without build target (which would be the same like using type "internal").

Closes #9

[manfredsteyer]

Thanks for this. I guess, this PR solves the first issue you are mentioning anyway. Regarding the 2nd point (testing), I'll have a look.