Theme switcher for more themes

[elizavetaRa]

Description

The pr adds the possibility to switch between themes when there are more than 2.

Related Issue

• Fixes <issue_link>

Motivation and Context

Improving the accessibility by providing high contrast themes in addition to classical default and default dark

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.

[elizavetaRa]

@tbsbdr
To discuss:

• icon (selected "paint", alternative: "paint-brush")
• Need of heading (I personally like with it to clarify the purpose)
• With heading looks better in card optic, without it could be done like roles menu

For further pr's: themes, theme names

[pascalwengerter]

Closing in favor of #9698, thanks for the initiative!