move xz (lzma) support out of sysroot

[heitbaum]

The follow changes allow the xz package to be moved out of sysroot

• The pre_configure_target for vfs.libarchive and pvr.iptvsimple allow xz to be linked in from outside the sysroot

xz:host is actually not used.
These are the changes to the packages:

• squashfs-tools: drop xz support
  • all images are currently zstd
• toolchain: drop xz:host DEPEND
• linux: drop xz:host DEPEND
• Python3: drop xz:host DEPEND

xz target changes:

• vfs.libarchive: use non sysroot xz
• pvr.iptvsimple: use non sysroot xz
• inputstream.ffmpegdirect: does not use xz

xz: drop host build

This PR maintains xz in the LE image: that being:

• image/system/usr/lib/python3.11/lib-dynload/_lzma.so