[engineering blog] devx / devx action / devx codespace

[angerman]

We should write a engineering.iog.io article about the devx repo that covers:

• motivation (why do we care at all?)
• basic haskell.nix understanding
• usage as GitHub action (example)
• nix usage of devx (example)
• usage of the devx CodeSpaces (example)

[yvan-sraka]

input-output-hk/engineering#65