Standardize the use of index files across top-level topics

[bgravenorst]

There is an inconsistency in how index files (index.md) are used across different top-level topics within the documentation. Specifically, some top-level topics contain content within their index.md files, while others do not. This inconsistency can lead to confusion for both users navigating our documentation and contributors maintaining it.

For this issue we may need to decide on a consistant approach first.

[Vtalike]

There is an inconsistency in how index files (index.md) are used across different top-level topics within the documentation. Specifically, some top-level topics contain content within their index.md files, while others do not. This inconsistency can lead to confusion for both users navigating our documentation and contributors maintaining it.

For this issue we may need to decide on a consistant approach first.