Allow host to specified for sharded MySQL installs. Also, move user, password, and port to make it easier for users to override the way these items are pulled
Merge pull request #44 from mortardata/ddaniels_mysql_extract_specify_host

[#84645390] Allow host to specified for sharded MySQL installs. Also, move user, password, and port to make it easier for users to override the way these items are pulled