docs: final check before launch

[adiati98]

Description

This PR holds changes as below:

• Adjusted wording in all chapters.
• Fixed formats.
• Added helpers for important and general tips.
• Fixed "Code of Conduct" term for consistency after some researches:
  • Use code of conduct (all lower case) to refer code of conduct in general.
  • Use Code of Conduct (capitalized) to refer to a specific code of conduct, such as an organization's CoC. For example: "OpenSauced Code of Conduct", "Read our Code of Conduct", etc.
  • Use codes of conduct when referring to plural codes of conduct. (resource: https://grammarbrain.com/plural-of-code-of-conduct/)
• Moved files from images to img folder and from gifs to gif folder, and remove the empty folders.
• Fixed links.

What type of PR is this? (check all applicable)

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

Related Tickets & Documents

Closes #42

Mobile & Desktop Screenshots/Recordings

Steps to QA

Added to documentation?

• 📜 README.md
• 📓 docs.opensauced.pizza
• 🍕 dev.to/opensauced
• 📕 storybook
• 🙅 no documentation needed

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

[optional] What gif best describes this PR or how it makes you feel?

[adiati98]

@BekahHW this PR depends on #71 and #73