Allow grouping in query builder entitySelect section

[dobromirts]

Is your feature request related to a problem? Please describe.

Currently the 'QueryBuilder' supports only listing of the entities in its 'selectFromTemplate'

1. It would be beneficial to include grouping functionality in this template, allowing users to organize different types of fields using labels and dividers as shown in the select component examples

2. Enhance the conditional action template to be fully templatable and customizable.

Details:
It would be valuable to support full templating of this structure, enabling developers to override and extend the default layout and behavior. A particularly useful enhancement would be to allow dropdowns to be integrated with each field, providing additional context-specific options or related fields. This would improve usability and make the interface more dynamic and adaptable to complex workflows.

Use Case Example:
When selecting a field in a condition, a dropdown could dynamically display related fields or options relevant to the selected field ,improving both discoverability and user experience.

Describe alternatives you've considered

As alternative the option to show 'igx-divider' as separation indicator would be also beneficial.