tests: xbps-rindex/add: rework some tests to use xbps-query -s rather than -Ro.
xbps-query/search: simplify.
lib/archive.c: remove support to read zplists in archives.

It was never used and the binpkgs are already compressed...
pkgdb: switch to zplists by default.
lib/portableproplib/prop_zlib.c: use a stack buffer to process compressed chunks.
tests: xbps-rindex/add: set rootdir to not use host repo.d