Add support for different templates and upgrade to Angular 12

[mraible]

Fixes #23.

[mraible]

npm test fails with:

    Failed: Could not find an NgModule. Use the skip-import option to skip importing in NgModule.
  Stack:
    Error: Could not find an NgModule. Use the skip-import option to skip importing in NgModule.
        at findModule (/Users/mraible/dev/angular-crud/angular-crud/node_modules/schematics-utilities/node_modules/@schematics/angular/utility/find-module.js:80:11)
        at Object.findModuleFromOptions (/Users/mraible/dev/angular-crud/angular-crud/node_modules/schematics-utilities/node_modules/@schematics/angular/utility/find-module.js:24:33)

I believe this is because schematics-utilities doesn't support Angular 12. If I change to use Angular CDK instead, it's a similar error.

[mraible]

@manfredsteyer Are you OK with the changes in e417492? This makes it so the generated code more closely aligns with what I'd expect. It also represents the changes I made in Build Beautiful Angular Apps with Bootstrap.

[mraible]

@manfredsteyer I decided to keep your theme as a set of templates referred to as paper-dashboard. If I'm able to add a set of templates for Angular Material, can you assist with a release in the next few days?

[mraible]

It probably makes sense to create demos for each framework (bootstrap, material, and paper-dashboard). Could require a few hours of work but will likely result in higher quality.

[mraible]

I added demos for Bootstrap and Angular Material. However, this is still more work to do. I need to figure out why the navbar doesn't show up in the origin demo. Once I get it working there, I'll try to get it working with the other examples.

There's also an issue with Angular Material where the height of the page is not dynamically calculated and the form's width is not calculated.

Update: I posted a question to Stack Overflow asking how to fix the dynamic height issue.

[mraible]

@manfredsteyer I updated the original demo to use Bootstrap 5 and fixed the navbar issue. I don't think the other demos really need the navbar, so I didn't include it. I'll QA this tomorrow (Monday) and it should be ready for a release shortly after.