[Slides] Add list of previously added slides

[Vija02]

Problem

Right now to add a slide, we need to click quite a lot of buttons.
Previously it was:

1. Add new scene 2. Slides 3. Confirm 4. PDF 5. Upload PDF 6. Browse files 7. Select file 8. Upload button

With the scene change, we've removed step 3 (the confirm/create button). And with the new project change, we also remove step 1 for new projects. Now we want to simplify the other steps.

Proposal

On new slide plugin, we should show:

• The upload area directly (accepts any of pdf, pptx, image)
• A separate section for sync integrations (google slides, later canva)
• "Recently added" section (this would replace the current media picker)

On pressing add, we open a modal. The contents of this modal will also be the same or very similar

Task

For this ticket:

• Add a component to select previously added slides

We can put this at the bottom of the page.

Acceptance criteria

• On add slides, i can see the previously added slides
• On click, the slides is added
• This is also in the add Modal

Tests

• Add test to ensure it appears
• Add test to ensure we can click and import it

[moon636]

I have pushed my initial attempt, could be carried on from there or started from scratch.