Minor updates the samples readme for codespaces

[danhellem]

Checklist

• I have read the [contribution guidelines] (https://github.com/Azure/azure-iot-sdk-node/blob/master/.github/CONTRIBUTING.md).
• I added or modified the existing tests to cover the change (we do not allow our test coverage to go down).
• If this is a modification that impacts the behavior of a public API
  • I edited the corresponding document in the devdoc folder and added or modified requirements.

Description of the problem

The codespaces content in the samples readme.md for devices needed to be updated

Description of the solution

updated the codespaces screen shot
fixes some links
simplified some content

[YoDaMa]

lgtm