esv2yaml must export /hst:hst/hst:hosts as config

Currently, esv2yaml injects .meta:residual-child-node-category for nodes under /hst:hst/hst:hosts and also moves child nodes to content. For local development, AutoExport supports an override for these paths such that the .meta:residual-child-node-category gets injected for new nodes, but keeps the child nodes as config. Esv2yaml must support a similar override mechanism.