Add integration points for Index.html image and Icon images

[phycodurus]

Currently, changing the image on the index.html template requires overriding the template in a TOM-specific tom_common/index.html. Often this is a copy/paste from the default template with very few changes (zum Beispiel). It seems like there is a potential integration point to make this customization easier and more modular.

• main image
• small icone
• browser tab icon

[jchate6]

Can you be more specific? Maybe an image to show what you are talking about?
Unless I'm misunderstanding, this is already available: https://tom-toolkit.readthedocs.io/en/stable/customization/customize_templates.html#customize-default-logos-and-icons

This might be a case of unclear or obfuscated documentation?