restore: add parallel snapmk snapshot repacker

Thread-parallel version of the snapshot repacker.  Beats zstdmt
version 1.5.5 by about 45% with 16 CPUs.

Author: riptl

src/discof/restore/Local.mk

@@ -47,5 +47,6 @@ $(call add-objs,utils/fd_vinyl_io_wd,fd_discof)
 ifdef FD_HAS_HOSTED
 ifdef FD_HAS_ZSTD
 $(call make-bin,fd_snapmk,fd_snapmk,fd_discof fd_flamenco fd_ballet fd_util)
+$(call make-bin,fd_snapmk_para,fd_snapmk_para,fd_discof fd_flamenco fd_ballet fd_tango fd_util)
 endif
 endif