multimedia/totem: port plugins to libsoup-2

https://gitlab.gnome.org/GNOME/totem/-/merge_requests/373
as one unified diff, as some affected files do not exist in the tarball

Also pull in some commits for functionality and to allow the unified
diff to apply:

• preferences: Modernise preferences UI
• preferences: Allow to disable hardware acceleration
• plugins: Remove support for configurable plugins
• plugins: Simplify TOTEM_PLUGIN_REGISTER() macro
• preferences: Move the plugins settings
• preferences: Simplify video widget refcounting
• skipto: Remove skipto plugin
• main: Document digits 1 through 9 skipping 10% to 90%
• opensubtitles: Use GResource for loading UI file
• opensubtitles: Move treeview columns creation to GtkBuilder
• opensubtitles: Use GtkComboBoxText instead GtkComboBox
• opensubtitles: Move GtkTreeModelSort to GtkBuilder
• icon-helpers: Require gnome-desktop 43 and newer

PR: 295335