Add harvester control process to build all GCMD vocabularies from configuration files

[hmaier-fws]

From PR #12:

New harvesters/src/gcmd-all.js

Along with the new harvester process is this control process that will build all the GCMD vocabularies listed in the config file harvesters/conf/gcmd-vocabularies.json. It also uses harvesters/conf/gcmd-all.json config file and generates resources/gcmd-vocabularies-dynamic.json.

New keywords files

To demonstrate the new GCMD harvester, new files for all the GCMD vocabularies are included.

New npm run scripts

package.json has new scripts

"gcmd": "node src/index.js source=gcmd",
"usgs": "node src/index.js source=usgs",
"sb": "node src/index.js source=sciencebase"

Main control process command line options

harvesters/src/index.js was modified to handle command line options. This allows only the specified source to be compiled and all other vocabularies to be ignored. It still uses the profiles-list.json file from mdProfiles.