Feat/fix preview buggyness

[kriskuiper]

Description

This PR does add a couple of things:

• [x] Add a 404 page to preview (should do this to master also)
• [x] Make preview environment render the custom 404 page with some kind of loading text so it is clear that the page is being built
• [x] Deploy preview branch on save and throttle saves so Vercel doesn't get overloaded with requests
• [x] Give the user feedback that their save is being worked on.

Testing

Unfortunately you can't test this... Please believe my green eyes and look at the code. 🥺

[vercel[bot]]

This pull request is being automatically deployed with Vercel (learn more). To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/kriskuiper/cmd-digital-playground/24glypb7o ✅ Preview: https://cmd-digital-playground-git-feat-fix-preview-buggyness.kriskuiper.vercel.app