Refactor hdf2splunk and splunk2hdf to use vendor provided javascript libs

[aaronlippold]

https://github.com/splunk/splunk-javascript-logging

https://dev.splunk.com/enterprise/docs/devtools/javascript/logging-javascript/logjsrequirementinstall/

We are seeing some very odd behaviour with using strait POST commands for pushing data to Splunk via the HEC. The connection also does not seem to be closing.

Suggest moving to using the standard splunk js lib and @types/splunk-logging.

This will also help us with better error collection, connection issues, SSL and --insecure support and logging our sending of logs :)

[aaronlippold]

we may want to also look at the spunk-sdk for javascript for heimdall splunk interface? I think we are using this already right?

[aaronlippold]

Also, can we double check that these libs support treeshaking ...

[camdenmoors]

@yarick Were you able confirm that using the management interface instead of the HEC interface is okay?