Fix remaining images (#3927)

Author: npentrel

assets/codelabs/code.png

@@ -6,10 +6,7 @@ layout: "empty"
 canonical: "https://codelabs.viam.com/guide/environment-variables/index.html"
 tags: ["APIs", "python"]
 description: "Learn how to use Python variables with Viam projects so your code runs smoothly from development to deployment."
-images:
-  [
-    "https://codelabs.viam.com/guide/environment-variables/img/d97c0b6eea8a399e.png",
-  ]
+images: ["/codelabs/envvar.png"]
 imageAlt: "Code and an environment variables file"
 authors: ["Joyce Lin"]
 languages: []

assets/codelabs/peopledetection.png

@@ -6,8 +6,7 @@ layout: "empty"
 canonical: "https://codelabs.viam.com/guide/home-assistant/index.html"
 tags: ["APIs", "python"]
 description: "Learn how to install the integration through the Home Assistant Community Store (HACS) and use a vision service to detect people from a camera connected to Home Assistant."
-images:
-  ["https://codelabs.viam.com/guide/home-assistant/img/a630d5dcaf9e11c7.png"]
+images: ["/codelabs/peopledetection.png"]
 imageAlt: "person detection"
 authors: ["Nick Hehr"]
 languages: []

assets/codelabs/plant-watering.png

@@ -6,10 +6,7 @@ layout: "empty"
 canonical: "https://codelabs.viam.com/guide/plant-watering-device-workshop/index.html"
 tags: ["APIs", "python"]
 description: "Learn how to physically assemble a functional plant watering device by connecting and wire the components and code the machine."
-images:
-  [
-    "https://codelabs.viam.com/guide/plant-watering-device-workshop/img/8a9dd22a936e4ba4.png",
-  ]
+images: ["/codelabs/plant-wateringover.png"]
 imageAlt: "wiring diagram"
 authors: ["Hazal Mestci"]
 languages: ["python"]

assets/codelabs/ts-rover.png

@@ -6,8 +6,7 @@ layout: "empty"
 canonical: "https://codelabs.viam.com/guide/drive-rover-ts/"
 tags: ["APIs", "python"]
 description: "Drive a rover in a square using the Viam TypeScript SDK."
-images:
-  ["https://codelabs.viam.com/guide/drive-rover-ts/img/57f6b6f01a2535b8.png"]
+images: ["/codelabs/ts-rover.png"]
 imageAlt: "An overhead view of a rover next to a UI to move it"
 authors: ["Joyce Lin"]
 languages: []