Add new GStreamer plugin with custom video sink for Clapper video player.
The main difference is that unlike the old one, this does not operate using `GtkGLArea`
anymore, but processes and displays `GdkTextures` directly through `GtkPicture` widget.
Also this one is installed like any other GStreamer plugin, thus can be used via
`gst-launch-1.0` binary or even by other GTK4 apps if they wish to integrate it.
In order to not depend on GL stuff at build time, this plugin uses seperate GModules
called "importers" in order to import different kind of memories into GdkTexture. This
allows expanding its capabilities further then we were able to do before.
Clapper is now available in official repos on both Fedora and openSUSE. Considering that, I will not have time to properly maintain them here, so they go away.
The github actions Flatpak action only allows to specify single source
for installing missing dependencies. This makes impossible to build
some things from "gnome-nightly" while others from "flathub" repo.
Work around this limitation by manually installing missing SDK
extensions from Flathub prior to using this git action.
With all apps and modules/plugins porting itself to libsoup3 we also need to do so.
It would appear as a good idea to conditionally import "3.0" and fallback to "2.4"
bindings here, but its not as loaded GStreamer plugins might use libsoup3 already
and we cannot have both libsoup2 and libsoup3 in a single process.
It used Broadway as an easy "reuse the same code into web application" way for me, but Broadway
is not very good for this. This feature should be made using some better dedicated framework for
building websites (so it can work better and support different screen sizes).
All the WebSocket functionality needed for this will remain (and be documented at a later point
when expanded and stable), so if anyone would like to make such remote controlling app, will be
free to do so (outside of Clapper code).
Someone might be holding a copied media info in which case tag
list ref count is not 1. Use gst_tag_list_make_writable to
assure that ref count is 1, so we can insert more tags into the list.
