Merge branch 'ds/midx-expire-repack'

"git multi-pack-index" learned expire and repack subcommands. * ds/midx-expire-repack: t5319: use 'test-tool path-utils' instead of 'ls -l' t5319-multi-pack-index.sh: test batch size zero midx: add test that 'expire' respects .keep files multi-pack-index: test expire while adding packs midx: implement midx_repack() multi-pack-index: prepare 'repack' subcommand multi-pack-index: implement 'expire' subcommand midx: refactor permutation logic and pack sorting midx: simplify computation of pack name lengths multi-pack-index: prepare for 'expire' subcommand Docs: rearrange subcommands for multi-pack-index repack: refactor pack deletion for future use