Well actually in the elasticsearch.yml you bound to the network with 0.0.0.0 which means it is bound to a network address / IP not localhost (i.e loopback which is not bound to the network) Then in the app-search.yml you are trying to access elasticsearch through localhost... which is not a network address.That probably not going to work. You need to be consistent... All localhost or all using network.... Not mix and match.
To make it work either comment out the network.host line in elasticsearch.yml (probably easiest)
Or in the app-search.yml
elasticsearch.host: http://localhost:9200
To use the IP of the host you are on.
elasticsearch.host: http://<hostip>:9200
You would probably need to change the kibana.yml as well