Add video about fundamental concepts for internal analytics

What does this MR do and why?

Add video about the fundamental concepts of internal analytics to docs, to ease the explanation and increase the chance that potential users of internal analytics understand the concepts

Screenshots or screen recordings

The linked video: https://www.youtube.com/watch?v=GtFNXbjygWo

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #422692 (closed)