feat: Run '/search' endpoint through Flask-Limiter

[petesfrench]

Done

• Runs '/search' endpoint through Flask-Limiter
• Implementation based on discussion here: https://github.com/alisaifee/flask-limiter/issues/401

QA

• Open demo and go to /search
• Do 3 search's and see they go through
• Try to do a 4th search and see you hit the rate limit

Issue / Card

Fixes https://warthogs.atlassian.net/browse/WD-12317

Help

QA steps - Commit guidelines

[petesfrench]

hey @carkod, you seem to have most context on this. Would you be able to take a look please?

[carkod]

No, this is supposed to be done on https://github.com/canonical/canonicalwebteam.search, if you do it here, you'll have double amount of rate limiting

Updated the ticket and specs with more information