Resolve "Update Sisense handbook page to have csv related information"

Why is this change being made?

We need to update the Sisense handbook page (https://about.gitlab.com/handbook/business-ops/data-team/periscope/) to have the new database image and database name as well as point out existing utilities to manipulate data in python.

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what

Closes #6444 (closed)