Add --print_config command line parameter to dump the effective confi…

[cbeer]

…guration to the console.

### solr_wrapper configuration ###
---
:download_dir: "/Users/cabeer/tmp"
:print_config: true
:version: 8.5.0
:verbose: false
:host: 127.0.0.1
:zookeeper_host: 127.0.0.1
:port: '8983'
:zookeeper_port: '9983'
:url: http://127.0.0.1:8983/solr/
:instance_dir: "/var/folders/58/71c4h5hs1nqg4780k242fmhw0000gq/T/solr-8.5.0"
:download_url: https://mirror.olnevhost.net/pub/apache/lucene/solr/8.5.0/solr-8.5.0.zip
:solr_zip_path: "/Users/cabeer/tmp/solr-8.5.0.zip"
:version_file: "/var/folders/58/71c4h5hs1nqg4780k242fmhw0000gq/T/solr-8.5.0/VERSION"
:mirror_url: https://mirror.olnevhost.net/pub/apache
:tmp_save_dir: "/var/folders/58/71c4h5hs1nqg4780k242fmhw0000gq/T/d20200409-97361-1rdbycr"
#####