feat(volume mounts): add support for mounting volumes into the melange build context #2946

Job	Run time
Build melange and add to artifact cache	34s
Build packages (bubblewrap, hello-wolfi)	1m 25s
Build packages (bubblewrap, glibc)	13m 18s
Build packages (bubblewrap, tini)	1m 12s
Build packages (bubblewrap, lzo)	1m 29s
Build packages (bubblewrap, bubblewrap)	1m 14s
Build packages (bubblewrap, gitsign)	2m 47s
Build packages (bubblewrap, guac)	4m 5s
Build packages (bubblewrap, mdbook)	3m 55s
Build packages (bubblewrap, s3cmd)	1m 11s
Build packages (bubblewrap, perl-yaml-syck)	1m 15s
Build packages (bubblewrap, ncurses)	2m 17s
Build packages (qemu, hello-wolfi)	2m 53s
Build packages (qemu, glibc)	14m 13s
Build packages (qemu, tini)	2m 11s
Build packages (qemu, lzo)	2m 11s
Build packages (qemu, bubblewrap)	2m 8s
Build packages (qemu, gitsign)	4m 5s
Build packages (qemu, guac)	4m 41s
Build packages (qemu, mdbook)	4m 55s
Build packages (qemu, s3cmd)	1m 34s
Build packages (qemu, perl-yaml-syck)	1m 43s
Build packages (qemu, ncurses)	2m 39s
	1h 17m 55s

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