Feature/WDSUS-43 Folder Restructure

[khleomix]

Closes WDSUS-43

What type of PR is this? (put an x to all applicable)

• [x] 🍕 Feature
• [x] 🐛 Bug Fix
• [ ] 📝 Documentation Update
• [ ] 🎨 Style
• [x] 🧑‍💻 Code Refactor
• [ ] 🔥 Performance Improvements
• [ ] ✅ Test
• [ ] 🤖 Build
• [ ] 🔁 CI
• [ ] 📦 Chore (Release)
• [ ] ⏩ Revert

Link to test

Test locally

Description

• Remove unused customizer settings
• Remove mobile menu template
• Rename src folder to assets

Related Tickets & Documents

Mobile & Desktop Screenshots/Recordings

N/A

Added tests?

• [ ] 👍 yes
• [x] 🙅 no, because they aren't needed
• [ ] 🙋 no, because I need help

Added to documentation?

• [x] 📜 README.md
• [ ] 📓 Confluence
• [ ] 🙅 no documentation needed

Others

• [x] 🦮 Is this issue accessible? (Section 508/WCAG 2.0AA)
• [x] 🙌 Does this issue pass all the linting? (PHPCS, ESLint, SassLint)

[optional] Are there any post-deployment tasks we need to perform?