feat(lite/component): UiSpinner

[ByScripts]

Check list

Check if done, if not relevant leave unchecked.

• [ ] PR reference the relevant issue (e.g. Fixes #007 or See xoa-support#42)
• [ ] if UI changes, a screenshot has been added to the PR
• [ ] documentation updated
• CHANGELOG.unreleased.md:
  • [ ] enhancement/bug fix entry added
  • [ ] list of packages to release updated (${name} v${new version})
• I have tested added/updated features (and impacted code)
  • [ ] unit tests (e.g. cron/parse.spec.js)
  • [ ] if xo-server API changes, the corresponding test has been added to/updated on xo-server-test
  • [ ] at least manual testing

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[ByScripts]

I make it so the spinner act as an icon (like <FontAwesomeIcon :icon="spinner" spin />).

I thought it would be much more flexible if it adjusted its size according to the font-size.

Moreover, it will be used in the UiIcon component <UiIcon :icon="faSomething" :busy="isBusy" /> and therefore will have the same size of the icon (which takes the size of the text).