Add database schema to documentation page

[MouseAndKeyboard]

What needs to be done?

@Tommo303 Created a lucid chart diagram for the database schema. This is great and we should add it to the developer documentation tab on the project documentation.
You should be able to embed the lucid chart diagram into the MkDocs so that it's interactive (and not just a png image).

For reference on how to do the embedding, please see: https://github.com/uwasystemhealth/IndEAA/blob/develop/mkdocs/docs/developer/data_engineering.md

Other

[Tommo303]

[frinzekt]

This needs to be embedded in the docs later

[MouseAndKeyboard]

@Tommo303 There should be a 1-to-many relationship between Justification of Course Evaluation---Course Evaluation

[frinzekt]

I noticed that within the documents while working on #47 , that the name and description of the document is missing