RFC: Introduce the Front Matter Headless CMS extension for VS Code

[leograba]

Dear Maintainers,

This PR is a suggestion to introduce support for the Front Matter Headless CMS for VS Code users.

• Unobtrusive: if you don't use VS Code or if you use VS Code but don't want to use this CMS, you can completely ignore it
• User-proof: it helps check blog metadata (I at least always forget something)
• Preview: it helps start a local server and generates a preview of the website in VS Code - which can all be done manually, but some may find the ease-to-use interesting
• UI: although it's an engineering blog and great for CLI users, some old tired guys such as the Torizon OS PO may enjoy the simplicity of a UI

Here's a screenshot to briefly illustrate it:

[microhobby]

@leonheldattoradex this seems very valuable! LGTM