Enhancement: Reuse `NumberExtension`

[localheinz]

What is the reason for this PR?

• [x] adjusts existing Extensions to reuse the NumberExtension

Somewhat related to #694.

💁‍♂️ If we want to provide a path towards using Random\Randomizer in the distant future, I believe it would be best to centralize the source of randomness.

This could be one step.

Author's checklist

• [x] Follow the Contribution Guide

Summary of changes

Review checklist

• [ ] All checks have passed
• [ ] Changes are approved by maintainer

[localheinz]

Thank you, @bram-pkg!