Bug 1712921 - Implement ping storage size limit

[brizental]

Pull Request checklist

• Quality: Make sure this PR builds and runs cleanly.
  • Inside the glean/ folder, run:
    • npm run test Runs all tests
    • npm run lint && npm run lint:circular-deps Runs all linters
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry to CHANGELOG.md or an explanation of why it does not need one
• Documentation: This PR includes documentation changes, an explanation of why it does not need that or a follow-up bug has been filed to do that work
  • This behaviour is already documented on the Glean book: https://mozilla.github.io/glean/book/user/pings/index.html?highlight=10MB#limitations