Add prompts for new cluster Capella

- Sort prompts by installation year

doc.zih.tu-dresden.de/docs/contrib/content_rules.md

@@ -411,15 +411,17 @@ This should help to avoid errors.
 | Localhost              | `marie@local$`   |
 | Login nodes            | `marie@login$`   |
 | Arbitrary compute node | `marie@compute$` |
+| Compute node `Capella` | `marie@capella$` |
+| Login node `Capella`   | `marie@login.capella$`  |
 | Compute node `Barnard` | `marie@barnard$` |
 | Login node `Barnard`   | `marie@login.barnard$`  |
-| Compute node `Power9`  | `marie@power9$`  |
-| Login node `Power9`    | `marie@login.power9$`  |
 | Compute node `Alpha`   | `marie@alpha$`   |
 | Login node `Alpha`     | `marie@login.alpha$`   |
+| Node `Julia`           | `marie@julia$`   |
 | Compute node `Romeo`   | `marie@romeo$`   |
 | Login node `Romeo`     | `marie@login.romeo$`   |
-| Node `Julia`           | `marie@julia$`   |
+| Compute node `Power9`  | `marie@power9$`  |
+| Login node `Power9`    | `marie@login.power9$`  |
 | Partition `dcv`        | `marie@dcv$`     |
 
 * **Always use a prompt**, even if there is no output provided for the shown command.