Ui/dark theme img fix

I'm missing a couple of fixes

Description

• Trello card: https://trello.com/c/QcOH4U8p/2008-product-brand-fix-all-images-to-work-on-dark-theme-xd

• Summary of the change:

In this PR I update the dark theme images in several pages. Usually, the images were embedded in the page with the img tag. This means that I've had to replace the tags with divs & CSS.

Please note that the graphics for the layout haven't been included since there's still work that needs to be done to them and will be added in a separate PR.

Type of change

• UX/UI Improvement
• Bug fix (non-breaking change which fixes an issue).
• 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.

How has this been tested?

I've updated all the graphics in the image:

Except for the ones for layout, since @manuelecarlini needs to do some updates to them.

I've also updated http://localhost:3000/tooltips/smart-tooltips

Browser testing

• Edge
• Firefox
• Chrome/Chromium
• Safari

Screenshots (if appropriate):

Checklist:

• My code follows the code style of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas [if needed].
• I have made corresponding changes to the documentation [if needed].
• My changes generate no new warnings.
• ⚠️ I have added tests that prove my fix is effective or that my feature works [if needed].
• New and existing unit tests pass locally with my changes.