Adds package group settings side-by-side layout

What does this MR do and why?

• Adds a new settings_block.vue with side-by-side layout
• use it within group settings for packages & registries

This MR is last of series of MRs related to #363424 (closed)

Screenshots or screen recordings

Desktop:

before	after

Mobile:

How to set up and validate locally

1. Visit 'Group' > 'Settings' > 'Packages & Registries'
2. Verify side by side layout

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.

Closes #363424 (closed)