Issue Summary

There is a use case for some customers where Confluence Automation rules are intended to take a portion of a page (isolated by RegEx expressions) and transmit them to their preferred code repository when triggered by a given condition. 

While Confluence currently has the capability to isolate a portion of a page by making a REST call to itself and then processing it by RegEx expression, as well as the ability to then take that output and transmit it as a web call to a specified host, a common requirement of other APIs is to have file contents encoded in base64 format, which Confluence currently does not support.

The request then is to add an "encode in base64" action to the list of available Confluence actions which would accept input and be able to pass its output on to another step for further processing.