Evaluate designs

Evaluate a number of design documents, sorting/merging into website properly. Make small improvements to main page in passing.

content/policies/images.md

@@ -132,9 +132,11 @@ each image type:
 | Type       | amd64 | armhf | arm64 | APT | OSTree | 
 | ---------- | ----- | ----- | ----- | --- | ------ |
 | Minimal    | ✅    | ✅    | ✅    | ✅  | ✅     |
-| Target     | ✅    | ✅    | ✅    | ✅  | ✅     |
+| Target     | ✅    | ✅ \* |       | ✅  | ✅     |
 | Base SDK   | ✅    |       |       | ✅  |        |
 | SDK        | ✅    |       |       | ✅  |        |
 | Sysroot    | ✅    | ✅    | ✅    |     |        |
 | Devroot    | ✅    | ✅    | ✅    | ✅  |        |
 | NFS        | ✅    | ✅    | ✅    | ✅  |        |
+
+\* Since v2020