Remove forRoot calls from ChartsModule

[CloudNiner]

For the ngx-bootstrap modules.

It's clear in the Angular documentation that forRoot() calls should only be made from the root AppModule. ChartsModule is not one of those so it shouldn't have the forRoot calls.

However, it's unclear how we should handle this here. If we remove the forRoot calls, then we break the abstraction of our library and require users to both include ngx-bootstrap as a dependency in the application that uses this lib and perform specific setup steps for this library, namely adding ngx-bootstrap module imports with the forRoot calls in their AppModule. If we don't remove the forRoot calls, we may have subtle breakage occur down the road. It may be worth investigating if theres a way to not break library abstractions and still call the appropriate ngx-bootstrap forRoot methods in the correct place.

In progress branch that implements the simple "remove the forRoot calls and let the parent handle it" case: https://github.com/azavea/climate-change-components/tree/feature/awf/remove-forroot