Bug 255980

When building with the minimal moduleset on Ubuntu 22.04, I got the following build error:

```
Found CMake: /usr/bin/cmake (3.22.1)
Run-time dependency gstreamer-video-1.0 found: NO (tried pkgconfig and cmake)
Looking for a fallback subproject for the dependency gstreamer-video-1.0

../../Source/gst-libav-1.18.4.tar.gz/meson.build:88:0: ERROR: Neither a subproject directory nor a gst-plugins-base.wrap file was found.

A full log can be found at /home/pwuser/webkit/WebKitBuild/WPE/DependenciesWPE/Build/gst-libav-1.18.4.tar.gz/meson-logs/meson-log.txt
meson setup --prefix /home/pwuser/webkit/WebKitBuild/WPE/DependenciesWPE/Root --libdir lib  --buildtype=debugoptimized /home/pwuser/webkit/WebKitBuild/WPE/DependenciesWPE/Source/gst-libav-1.18.4.tar.gz
Failed to build WPE port dependencies with jhbuild
Died at ./Tools/Scripts/update-webkitwpe-libs line 26.
```

Ubuntu 22.04 satisfies all the required dependencies provided by the GStreamer moduleset through system libraries. In theory, the pkg-config tag should prevent installing the modules provided by GStreamer if a more up-to-date version of that package is available through system dependencies. However, some modules lack a .pkg file so it's not possible to do this in all cases.

An alternative solution could be to restore the former jhbuild-minimal moduleset and add a new one which also includes the gstreamer modules. Those systems that cannot satisfy gstreamer dependencies through system libraries can use this new minimal-plus-gstreamer moduleset.