Wordings : Enhancement of background and UI color change thanks to better title and description

[Jerome-Herbinet]

Summary

Everything is in the PR's title and in the commit.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[Jerome-Herbinet]

Question :
Some other files than "dist/theming-personal-theming.js" and "dist/theming-personal-theming.js.map" have been generated by my first "npm run build", but haven't been regerated after by my others "npm run build". Is this normal ?

[jancborchardt]

Thank you! :)

[skjnldsv]

@Jerome-Herbinet can you rebase and solve the conflicts? :)
I'd like to merge this 🚀