Include Web App Tutorial in README.md

[KelsonDenton]

Proposed Changes

• Adding a tutorial for the web application to make it easier to dive into the basic functionality of the app
• Updated README.md and added image files that are included in the tutorial

Please check that the PR fulfills these requirements

• [ ] Tests for the changes have been added (for bug fixes / features)
• [ ] Added yourself to AUTHORS.rst

Other questions

• Do users need to run some commmands in their local instances due to this PR (e.g. database migration)?