Renamed "file" to "file_render", added new "file"

The new "file" template function loads only the bytes of the file (as string) without further processing. "file_render" now does what "file" did before and that is calling the Go template engine to render the contents of the passed file as template. This was done for performance reasons as loading a file and passing it to the Go template engine if no processing is required can slow down tests quite a biit.

What's Changed

• using break and collect responses format by @unai-programmfabrik in #63
• don't overwrite format if unset (see #63710) by @mad-pf in #71

New Contributors

• @mad-pf made their first contribution in #71

Full Changelog: v1.5.0...v1.6.0