community/gtk4.0: move dev tools and valgrind .supp to -dev subpkg & move gstreamer backend to -media-gstreamer subpkg

move gstreamer backend to -media-gstreamer subpkg

GStreamer is pretty huge dependency that is needed only for some applications. For example, Debian provides it in a separate package (libgtk-4-media-gstreamer) too.

gtk4.0-media-gstreamer should be added as a dependency to the packages that actually need it. Unfortunately, I don't know which ones are they at this moment.

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Already merged

move dev tools and valgrind .supp to -dev subpkg

gtk4-builder-tool, gtk4-encode-symbolic-svg, gtk4-query-settings are not needed for running applications (as I know), these are development tools. For example, Fedora provides them in subpackage gtk4-devel, Debian in libgtk-4-bin.

This decreases size of the gtk4.0 package from 16.4 MiB to 9.0 MiB.

move localized emoji labels to -lang subpkg

This will reduce size of the gtk4.0 package from 9 MiB to 8.6 MiB.