* Separate bulk upload behavior from CollectorSet

 - takes out a lot of behavior from CollectorSet and moves it to a class called BulkUploader
 - simplifies kibana monitoring init by taking out the indirection that startCollectorSet / createCollectorSet had
 - removes start() method from CollectorSet and calls the collector objects' init() functions from CollectorSet.register()
 - removes cleanup method from collectorSet since that was doing work for bulk uploading

* remove cleanup and fetchAfterInit methods

* test for bulk_uploader class

* improve test for collector_set

* fix reporting

* expose collectorSet if there actually is a collectorSet

* comment for enclosed function

* make collectorSet creation/expose unconditional, bulkUploader more conditional

* fix collector_set tests

* lifecycle events

* stab at collectorSet error logging from the API call

* clean up comments

* clean up comments

* fix BulkUploader mocha test

* check kibanaCollectionEnabled config before registering bulk upload and the plugin status listeners

* no singleton timer object

* just log a warning if bulk uploader start called twice

* normal quotes

* check if bulk is enabled inside of the _fetchAndUpload method

* log for stopping bulk stats

* call bulkUploader.start with the collectorSet object

* call bulkUploader.start with the collectorSet object

* roll back change for module scoped variable

* oops I broke init

* init and logging: if / elseif / elseif

* remove unnecessary check/log

* help log

* remove redundant, use data.filter.map

* use xpackInfo.onLicenseInfoChange not xpackMainPlugin.status.on('green')

* help logging

* fix unit test

* remove handler that stops upload when connection is lost