Implement shlib checks for all pkg revdeps in the transaction.

Added three new test cases to verify its correctness.
NEWS: improve wording.
xbps-{install,query}.8: sync with reality.
xbps.h: update comments.
Drop unused headers.
pkgdb: repository-origin -> repository to match the repo pkg obj.
tests/libxbps/replace: check that pkgs were configured too.

These two tests currently fail.
tests/libxbps/replace: add more debugging to see what's going on.
xbps_transaction_commit: add more debugging to know the unconfigured pkg reason.
xbps_register_pkg: do not modify the transaction pkg dictionary, use a copy instead.

Due to not using a copy the replace tests were failing at the configure phase,
because the "transaction" object was removed.
lib/pkgdb_conversion.c: avoid copying dangling pointer if "repository-origin" is unexistent.
Add xbps_remove_{pkgname,string}_from_array() to the API.
Remove pkg self replacement from pkgdb; this must not be propagated.
tests/libxbps/replace: another test case for replaces and vpkgs.
libxbps: fixed replaces/replace_vpkg test case.
tests: two new tests to verify pkg install/update with no files.
Fixed install/update tests on pkgs with no files.
Remove empty self replaced pkg arrays from pkgdb.
etc/xbps.conf: sync with reality.
NEWS: prepare 0.38.