Add layout for settings redesign

[flozia]

References:

Jira: MNTOR-3675
Figma: https://www.figma.com/design/2iCgADpFXKOFZTEgCPkQsR/Settings?node-id=6-17580&t=uQL3qalyCpHOWgWx-4

Description

Adds the new layout for the settings page redesign and is behind the feature flag SettingsPageRedesign. The panel content will be implemented separately:

• Edit your info: MNTOR-3803
• Set notifications: MNTOR-3676
• Manage account: MNTOR-3677

Screenshot

Panels

Edit your info	Set notifications	Manage account

Mobile menu

How to test

1. Enable the feature flag SettingsPageRedesign.
2. Visit the settings page /user/settings.

Checklist (Definition of Done)

• Localization strings (if needed) have been added.
• Commits in this PR are minimal and have descriptive commit messages.
• I've added or updated the relevant sections in readme and/or code comments
• I've added a unit test to test for potential regressions of this bug.
• If this PR implements a feature flag or experimentation, the Ship Behind Feature Flag status in Jira has been set
• Product Owner accepted the User Story (demo of functionality completed) or waived the privilege.
• All acceptance criteria are met.

[github-actions]

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