Move xbps_read_dict_from_archive_entry() and friends into its own file.

lib/Makefile

@@ -43,7 +43,7 @@ OBJS += package_unpack.o package_requiredby.o package_register.o
 OBJS += package_purge.o package_replaces.o package_properties.o
 OBJS += transaction_dictionary.o transaction_sortdeps.o
 OBJS += cmpver.o download.o fexec.o humanize_number.o plist.o
-OBJS += util.o pkgmatch.o mkpath.o initend.o
+OBJS += plist_archive_entry.o util.o pkgmatch.o mkpath.o initend.o
 OBJS += regpkgdb_dictionary.o repository_register.o
 OBJS += repository_findpkg.o repository_plist.o repository_finddeps.o
 OBJS += repository_pool.o repository_sync_index.o