[Task](ui): implement TabBar appereance="buttons" #2028

Task Description

Implement the new stylistic variation of TabBar as designed, and so we have it available for pre-defined filters in DataGrid. While at it, the current appearance="content" appearance="main" should become appearance="tabs", which should be the default value for appearance. The "content" should remain functional for now, but marked as deprecated in favour of "tabs". "main" should remain functional for now but be marked as deprecated in favour of "tabs". "content" should also remain functional as a distinct style variant.

The new variant should be represented in storybook, the necessary tests added.

The appearance="buttons" variation has been implemented as a standalone component already, so the PR at #2020 can be used as a reference for implementation, but should not be merged but deleted once this issue is completed.

Visual Design

https://www.figma.com/design/kpxMkXyQ2bsdQ1xjX8gAaN/%25F0%259F%259F%25A2-DS_HF-Style-Guide-Library?node-id=5278-78498&t=oQxWseUEMeWum0b5-0

Related Issues

Relies on #1986 / merging of #2019