fix(grid,tree-shake): use lightweight token for paginator

[damyanpetev]

Added a DI alias for the paginator using a lightweight token and swapped the content queries in the grids to use it instead so the component can be tree-shaken when not in use.
Note, it's not a "by-the-book" lightweight token implementation since the IgxPaginatorComponent still extends DisplayDensityBase and I didn't want to mix that with the token. Instead, left a comment since the density is deprecated and will be dropped eventually. Also, the paginator prop on the grids is still part of the public interface (even as hidden) and I left that with just type imports to avoid propagating the change further and will leave that again for later once the public interface is cleaned up.

Results:
Given the app imports just IgxGridComponent, IgxColumnComponent before and after:

Small win, but the correct approach for this type of child component relations nonetheless :)

Additional information (check all that apply):

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them

[kdinev]

Please include an CHANGELOG.MD update.

[damyanpetev]

Please include an CHANGELOG.MD update.

Will make a 3rd PR for the action strip and will add the changelog there to avoid conflicting with the current 2