docs: Add section on running external tools in flatpak to installation

And link from platforms.

Signed-off-by: Joaquim Rocha <joaquim.rocha@microsoft.com>

Author: joaquimrocha

docs/installation/desktop/linux-installation.md

@@ -30,6 +30,19 @@ To upgrading Headlamp when it's installed via Flatpak, run:
 flatpak update io.kinvolk.Headlamp
 ```
 
+### Running External Tools
+
+When using tools like `az`, `aws`, `gcloud`, etc. from e.g. kubeconfig user's
+exec, Flatpak will need to run these tools from outside the sandbox. For that
+to work, you need to grant the *talk-name* of *org.freedesktop.Flatpak*. To do
+this, use the [Flatseal](https://flathub.org/apps/com.github.tchx84.Flatseal)
+application to change Headlamp's permissions, or run the following command
+(before running Headlamp):
+
+```shell
+sudo flatpak override --talk-name=org.freedesktop.Flatpak io.kinvolk.Headlamp
+```
+
 ## AppImage
 
 Headlamp can be used as an [AppImage](https://appimage.org/) by downloading and running it directly.

docs/platforms.md

@@ -47,7 +47,7 @@ We test on MacOS, various flavours of Linux, and Windows. Headlamp runs in the b
 | MacOS (arm, x86)                   |  ✔️   |
 | Ubuntu 20.04, 22.04, 22.10         |  ✔️   |
 | Fedora                             |  ✔️   |
-| Flatpak                            |  ✔️   | When using external tools like `az`, `aws`, `gcloud`, etc., please run `sudo flatpak override --talk-name=org.freedesktop.Flatpak io.kinvolk.Headlamp` before running Headlamp, so those tools can be called from within the sandbox. |
+| Flatpak                            |  ✔️   | See [running external tools from Headlamp](/docs/latest/installation/desktop/linux-installation#running-external-tools) if you need to use `az`, `aws`, `gcloud`, etc. in your kubeconfig |
 
 
 ## CNCF and Kubernetes Integrations