Inform users about Pyside6 and conmon packages

Inform users that for specific distros and versions, we install some
extra packages (PySide6, conmon), in order to fix some incompatibilities
between Dangerzone and the base system. Provide also a link to the
source / build instructions for the package, as well as any relevant
issues.

Fixes #767

BUILD.md

@@ -4,6 +4,9 @@
 
 Install dependencies:
 
+<table>
+  <tr>
+      <td>
 <details>
   <summary><i>:memo: Expand this section if you are on Ubuntu 22.04 (Jammy).</i></summary>
   </br>
@@ -20,10 +23,15 @@ Install dependencies:
   sudo cp ./dev_scripts/apt-tools-prod.pref /etc/apt/preferences.d/
   ```
 
+  The `conmon` package provided in the above repo was built with the
+  following [instructions](https://github.com/freedomofpress/maint-dangerzone-conmon/tree/ubuntu/jammy/fpf).
   Alternatively, you can install a `conmon` version higher than `v2.0.25` from
   any repo you prefer.
 
 </details>
+    </td>
+  </tr>
+</table>
 
 ```sh
 sudo apt install -y podman dh-python build-essential fakeroot make libqt6gui6 \

INSTALL.md

@@ -57,6 +57,26 @@ Dangerzone is available for:
   </tr>
 </table>
 
+<table>
+  <tr>
+    <td>
+<details>
+  <summary><i>:information_source: Backport notice for Ubuntu 24.04 (Noble) users regarding the <code>conmon</code> package</i></summary>
+  </br>
+
+  The `conmon` version that Podman uses and Ubuntu Jammy ships, has a bug
+  that gets triggered by Dangerzone
+  (more details in https://github.com/freedomofpress/dangerzone/issues/685).
+  To fix this, we provide our own `conmon` package through our APT repo, which
+  was built with the following [instructions](https://github.com/freedomofpress/maint-dangerzone-conmon/tree/ubuntu/jammy/fpf).
+  This package is essentially a backport of the `conmon` package
+  [provided](https://packages.debian.org/source/oldstable/conmon) by Debian
+  Bullseye.
+</details>
+    </td>
+  </tr>
+</table>
+
 Add our repository following these instructions:
 
 Download the GPG key for the repo:
@@ -110,6 +130,23 @@ sudo apt install -y dangerzone
 
 ### Fedora
 
+<table>
+  <tr>
+    <td>
+<details>
+  <summary><i>:information_source: Backport notice for Fedora users regarding the <code>python3-pyside6</code> package</i></summary>
+  </br>
+
+  Fedora 39+ onwards does not provide official Python bindings for Qt. For
+  this reason, we provide our own `python3-pyside6` package (see
+  [build instructions](https://github.com/freedomofpress/maint-dangerzone-pyside6))
+  from our YUM repo. For a deeper dive on this subject, you may read
+  [this issue](https://github.com/freedomofpress/dangerzone/issues/211#issuecomment-1827777122).
+</details>
+    </td>
+  </tr>
+</table>
+
 Type the following commands in a terminal:
 
 ```

dev_scripts/qa.py

@@ -187,6 +187,9 @@
 
 Install dependencies:
 
+<table>
+  <tr>
+      <td>
 <details>
   <summary><i>:memo: Expand this section if you are on Ubuntu 22.04 (Jammy).</i></summary>
   </br>
@@ -203,10 +206,15 @@
   sudo cp ./dev_scripts/apt-tools-prod.pref /etc/apt/preferences.d/
   ```
 
+  The `conmon` package provided in the above repo was built with the
+  following [instructions](https://github.com/freedomofpress/maint-dangerzone-conmon/tree/ubuntu/jammy/fpf).
   Alternatively, you can install a `conmon` version higher than `v2.0.25` from
   any repo you prefer.
 
 </details>
+    </td>
+  </tr>
+</table>
 
 ```sh
 sudo apt install -y podman dh-python build-essential fakeroot make libqt6gui6 \