✨(frontend) adjust doc emoji behaviour and introduce emoji picker

[olaurendeau]

Purpose

Adjust the behaviors of Doc title emojis in Home page, Doc tree and Doc editor following discussion on #1358 (comment)
Here is a video displaying those new behaviours

Proposal

• Home page - remove standard icon replacement by doc emoji
• Doc header - emoji picker before the title + removal button in menu
• Doc Tree - emoji picker before the title + removal button in menu
• Interlinking - Display emoji instead of standard icon
• Multiple EmojiPicker Problem : It was possible to trigger multiple picker from Callout or DocIcon, adding an overlay to close the picker fixed the issue.

Illustrations

External contributions

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• I have read and followed the contributing guidelines
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• I have signed off my commits with git commit --signoff (DCO compliance)
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• My commit messages follow the required format: <gitmoji>(type) title description
• I have added a changelog entry under ## [Unreleased] section (if noticeable change)
• I have added corresponding tests for new features or bug fixes (if applicable)