The SQL logic in this file for package metadata now exactly
reflects RPC's search logic, without searching for specific
packages.

Two command line arguments are available:

    --extended | Include License, Keywords and Groups fields
    --all      | Include License, Keywords, Groups, dependencies and
                 relations

When one of these arguments are passed, the script will create
a packages-meta-ext-v1.json.gz, configured via packagesmetaextfile.

Done this way so that there are multiple options for archive;
the roughly 2.4MB basic metadata (-meta-v1) and the
~4-7MB (--extended) / 9.8MB (--all) metadata (-meta-ext-v1).

Archive JSON is in the following format: line-separated package objects
enclosed in a list:

    [
    {...},
    {...},
    {...}
    ]

This allows users to stream the archive and process packages
line-by-line, during the local storage process.

Signed-off-by: Kevin Morris <kevr@0cost.org>