FR: Allow exports using Go text/template

[predictiple]

We can export results to csv or json, but it would be nice to be able to process the data with templating and then export it to text. This allows custom output formats to be defined, for example markdown or asciidoc, which can then be processed externally to create pretty reports and relieves us of the burden of providing pretty report formats.

Examples of other tools that have this are Vale and Steampipe.

However these tools use templates defined in external tmpl files. We would prefer to define and use these templates via the GUI. The templates should ideally be independent of artifacts so that they can be used in various places, for example a template could be defined and used across all Hunts.

[scudette]

It is not clear to me how this differs from custom notebooks? We use the notebook as a way to generate some reporting and they can also be exported to html.

[scudette]

This is probably covered by the template() function now https://docs.velociraptor.app/vql_reference/other/template/