feat: upgrade to Angular 13 and support its modern package format

[arturovt]

Since Angular 13 has removed the View Engine support we can now switch to the partial compilation to accommodate with APF (Angular Package Format), the partial compilation was enabled but ng-packagr wasn't used to build the library:

I've added the ng-packagr which is a standard for building Angular libraries. It'll automatically create a dist folder and move all built assets there. You can now publish the library from the dist folder:

npm run build && cd dist && npm publish ...

This's a breaking change and might be published as a major version (@ng-click-outside@10).

[arkon]

Thanks for taking the time to contribute, but I've decided to stop maintaining this package. For more details, check out https://github.com/arkon/ng-sidebar/issues/229

If you're interested in maintaining a fork, please do feel free to do so!