Remove `classname` Package and Utilize Stencil's Conditional Class Rendering

[janivo]

Description

Stencil is capable of rendering conditional classes by itself, making our classname package obsolete. See Stencil's dependency suggestions for more details.

Acceptance Criteria

• All components previously using the classname package have been refactored to use Stencil's conditional class rendering.
• The classname package has been removed from the project's dependencies.