Add a setting to show room avatars

[mgwalker]

Description

• Adds a settings slider to enable/disable room avatars in the navigation panels

• If enabled, room avatars are shown in navigation panels

Motivation: Having room avatars visible helps many users quickly identify channels.

Fixes #107

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings

[github-actions[bot]]

All contributors have signed the CLA ✍️ ✅
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[mgwalker]

I have read the CLA Document and I hereby sign the CLA

[github-actions[bot]]

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[ajbura]

closing as per the previous feedback.