Edit 'Default values in repeats'

To add or refer to`` action to add defaults with the odk-new-repeat (and odk-instance-first-load) events.

Perhaps `jr:template` can be removed entirely as it has become obsolete (once pyxform no longer outputs it).

Though need to check how pyxform outputs static defaults for repeats.

Review the specification sections covering the odk-new-repeat and odk-instance-first-load events, the action, and jr:template. Compare how pyxform outputs static defaults for repeats, then define whether defaults should use and whether jr:template can be removed.

Written by the indexing model from the issue text.