avcodec: on encoding, try to match vlc and avcodec formats

This can avoid unnecessary format conversion.
avcodec: set default channel layout on encoding
Qt4: clarify PNAP dialog (fixes #8100)

Also remove #ifdef from translated string since gettext can obviously
not deal with that.
Qt4: remove isFirstRun parameter

This is totally redundant. qt-privacy-ask does the exact same thing.
Qt4: grammar
macosx: do registration of the log callback slightly later

This fixes mysterious interface crashes during startup, because of wrong / corrupt
initialization of several objects.
lua: remove dead code
lua: remove unused argument
lua: remove unused parameter
visual: remove abusive VLC_USED qualifier

Confusingly enough, aout_filter_RequestVout() is also used to release
the vout. In that case, ignoring the return value is perfectly fine.
adjust: removed unused values
yadif: use uintptr_t when casting pointer to integer
ncurses: remove cargo cultivated vlc_object_alive()

The ncurses thread is stuck in getch(). Checking vlc_object_alive()
does not solve anything.
core: intf: simplify intf_DestroyAll()
lua: do not check for should_die (always false here)
lua: remove should_die (always false here)
playlist: remove impossible code

Nothing calls vlc_object_kill() on the playlist.
media library: good riddance

Big pile of non-sensical and unmaintained code.
sqlite: remove useless plugin
core: remove media library support