palomar: update to OS 2.13; add kuromoji plugin

cmd/palomar/Dockerfile.opensearch

···
-FROM opensearchproject/opensearch:2.5.0
+FROM opensearchproject/opensearch:2.13.0
 RUN /usr/share/opensearch/bin/opensearch-plugin install --batch analysis-icu
+RUN /usr/share/opensearch/bin/opensearch-plugin install --batch analysis-kuromoji

cmd/palomar/README.md

···
 
 ## Development Quickstart
 
-Run an ephemeral opensearch instance on local port 9200, with SSL disabled, and the `analysis-icu` plugin installed, using docker:
+Run an ephemeral opensearch instance on local port 9200, with SSL disabled, and the `analysis-icu` and `analysis-kuromoji` plugins installed, using docker:
 
     docker build -f Dockerfile.opensearch . -t opensearch-palomar
-    docker run -p 9200:9200 -p 9600:9600 -e "discovery.type=single-node" -e "plugins.security.disabled=true" opensearch-palomar
+
+	# in any non-development system, obviously change this default password
+    docker run -p 9200:9200 -p 9600:9600 -e "discovery.type=single-node" -e "plugins.security.disabled=true" -e OPENSEARCH_INITIAL_ADMIN_PASSWORD=0penSearch-Pal0mar opensearch-palomar
 
 See [README.opensearch.md]() for more Opensearch operational tips.
 

cmd/palomar/README.opensearch.md

···
 
 # Basic OpenSearch Operations
 
-We use OpenSearch version 2.5+, with the `analysis-icu` plugin. This is included automatically on the AWS hosted version of Opensearch, otherwise you need to install:
+We use OpenSearch version 2.13+, with the `analysis-icu` and `analysis-kuromoji` plugins. These are included automatically on the AWS hosted version of Opensearch, otherwise you need to install:
 
     sudo /usr/share/opensearch/bin/opensearch-plugin install analysis-icu
+    sudo /usr/share/opensearch/bin/opensearch-plugin install analysis-kuromoji
     sudo service opensearch restart
 
 If you are trying to use Elasticsearch 7.10 instead of OpenSearch, you can install the plugin with:
 
     sudo /usr/share/elasticsearch/bin/elasticsearch-plugin install analysis-icu
+    sudo /usr/share/elasticsearch/bin/elasticsearch-plugin install analysis-kuromoji
     sudo service elasticsearch restart
 
 ## Local Development

cmd/palomar/main.go

···
 		&cli.StringFlag{
 			Name:    "elastic-password",
 			Usage:   "elasticsearch password",
-			Value:   "admin",
+			Value:   "0penSearch-Pal0mar",
 			EnvVars: []string{"ES_PASSWORD", "ELASTIC_PASSWORD"},
 		},
 		&cli.StringFlag{