Provide tagfn templating functions. Support only consuming tags and tagged content. tagfn functions are meant to be used in a template script to render tag-based navigation and tagged content.

Examples:

• getTagList()
• getTagsByContent(content)
• getContentByTag(tags, workspace). This function might fit better into cmsfn templating functions where we already provide methods to get content by path, by ID and by template ID. Compare with cmsfn and catfn and decide which templating function class should host this function. Where would a template developer expect to find it?