chore: add Periodic table database lab to main repo

[jdwilkin4]

We are adding the entire relational database projects to the frontend cert. We are adding everything as is.

For this issue, add the Periodic table database project to the main repo.

https://www.freecodecamp.org/learn/relational-database/build-a-periodic-table-database-project/build-a-periodic-table-database

make sure to keep the same ids

The only change you should make is to the remove the following sentence

This is one of the required projects to earn your certification.