feat(curriculum-build): add meta schema and normalize meta

[moT01]

This adds a schema validator for the meta.json files so there isn't any inconsistencies is less inconsistencies.

It removes four things in the meta.json files:
template values that are an empty string
required values that are an empty array
time values that are an empty string
superOrder values

Quite sure they aren't needed.

Also, formats a few files to use two spaces instead of four.

Checklist:

• I have read and followed the contribution guidelines.
• I have read and followed the how to open a pull request guide.
• My pull request targets the main branch of freeCodeCamp.
• I have tested these changes either locally on my machine, or GitPod.

Closes #XXXXX

[moT01]

I'm gonna see if I can add some tests

[ojeytonwilliams]

Has validation ❤️. A+ would review again.