Consider moving the "Customize this article" menu on the right side and sticky when visualizing article translation changes

[emilghittasv]

Describe the bug
Initially filled in https://bugzilla.mozilla.org/show_bug.cgi?id=1709852

Preconditions
Sign in to SUMO

Steps to reproduce
Steps to reproduce the behavior:

1. Navigate to a translated article (example: https://support.mozilla.org/it/kb/backup-dati-firefox-trasferire-su-altro-dispositivo)
2. Click on the "Modifica articolo" option.
3. Scroll down and click on the "Anteprima dei contenuti" option.

Expected behavior
The "Personalizza questo articolo" section (os/version selector) is positioned on the right side of the page and sticky following along users scroll/navigation through the translation edit.

Actual behavior
The "Personalizza questo articolo" section (os/version selector) is positioned at the top of the article preview making it hard for editors to locate the exact point you were before when visualizing different article content based on the information provided in the os/version configurator.

Desktop:

• OS: Firefox.
• Browser: Windows 10

Additional Information
A possible implementation is to mimic what we currently have for en-US articles when clicking on the "Preview Content" option. -> https://support.allizom.org/en-US/kb/error-codes-secure-websites/edit#preview (notice how the "Customize this article" section follows along with the user scroll).