Create OPNsense plugin to export to Splunk using HTTP Event Collector

Important notices
Before you add a new report, we ask you kindly to acknowledge the following:

• [x ] I have read the contributing guide lines at https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md
• [x ] I have searched the existing issues, open and closed, and I'm convinced that mine is new.
• [ x] When the request is meant for an existing plugin, I've added its name to the title.

Is your feature request related to a problem? Please describe.
Splunk is used by many. Syslog is good, but I think the HTTP event collector is a far easier method for shipping logs to Splunk. I have been using syslog and I have installed the Splunk forwarder on the firewall. The HEC exporter I developed seems to be more performant.

Describe the solution you'd like
I would like to see a plugin to support exporting logs over HTTP to a Splunk instance.

Describe alternatives you've considered
I have developed the plugin and I am interested in sharing it with the community.

Additional context

The issue names no files, tests, or entry points; start by reading CONTRIBUTING.md and examining existing OPNsense plugins that export logs. Determine how the proposed Splunk HTTP Event Collector plugin should be integrated and tested, with a working, maintainable log exporter and documented configuration as the completion criteria.