Fix robotools documentation index

[luisawachtendonk]

Update the robotools documentation index with missing modules.

[michaelosthege]

looking at the preview build (link is among the 6 successful checks ✔️) the fluenttools, worklist, utils and tramsform modules appear to be missing.
If you check the other files next to index.rst you'll find that some may require fixing while others are missing.

To build the docs locally (if you don't want to wait for the pipeline) you can install the /docs/requirements.txt and use make html from within the docs folder.

[michaelosthege]

💯