Add back runtime.c --appimage-extract-and-run

[probonopd]

• Add back --appimage-extract-and-run
• Possibly print a command that can dump ELF sections

[probonopd]

--appimage-extract-and-run is implemented.

[probonopd]

But does not seem to work always, e.g., here on FreeBSD:

FreeBSD% env TARGET_APPIMAGE=~/Downloads/PrusaSlicer-2.4.0-alpha1+linux-x64-202109011425.AppImage ./runtime-fuse2-x86_64 --appimage-extract 
Cannot open ~/Downloads/PrusaSlicer-2.4.0-alpha1+linux-x64-202109011425.AppImage: No such file or directory
Failed to get fs offset for ~/Downloads/PrusaSlicer-2.4.0-alpha1+linux-x64-202109011425.AppImage

But this works (apart from the fact that we haven't compiled in zlib here, which can easily be changed):

FreeBSD% cp ~/Downloads/PrusaSlicer-2.4.0-alpha1+linux-x64-202109011425.AppImage PS.AppImage
FreeBSD% env TARGET_APPIMAGE=PS.AppImage ./runtime-fuse2-x86_64 --appimage-extract
Squashfs image uses zlib compression, this version supports only zstd.
Failed to open squashfs image

So somehow the path parsing seems to be messed up?