Klaw docs - describe checks on raised requests

# What is currently missing?

Currently there are several checks done in klaw backend, when any request is made.
Ex : If a topic delete request has to be submitted, look for if there are any acls, or open requests.

# How could this be improved?

It would be nice if we document all these conditions on all the requests for all entities

# Is this a feature you would work on yourself?

* [ ] I plan to open a pull request for this feature