Moving number_to_human_size to a shared folder

What does this MR do and why?

Moves number_to_human_size.vue component to a shared folder. number_to_human_size is a wrapper around numberToHumanSize fn from app/assets/javascripts/lib/utils/number_utils.js.

Screenshots or screen recordings

No changes. Just sharing how it visually looks:

How to set up and validate locally

Open group (e.g. http://localhost:3000/groups/gitlab-org/-/usage_quotas#storage-quota-tab) and project (e.g. http://127.0.0.1:3000/gitlab-org/gitlab-test/-/usage_quotas#storage-quota-tab) usage quotas, ensure that the storage usage is properly displayed (e.g. 10 GiB)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.