Moving shards to marvel_shards documents

- Closes elastic/elasticsearch#498
- Remove redundant column on shard visualization
- Fix colspan on index view with unassigned shards
- Add /marvel/api/v1/clusters/{cluster_uuid}/state/{state_uuid}/shards
- Change shard vis to use id and type to request data from new shards
  api
- Change indexer to use new shard schema

Original commit: elastic/x-pack-elasticsearch@416e1c7fd4

marvel_index_template.json

@@ -207,8 +207,19 @@
     },
     "marvel_shards": {
       "properties": {
+        "state_uuid": {
+          "type": "string",
+          "index": "not_analyzed"
+        },
         "shard": {
-          "type": "object"
+          "properties": {
+            "state": { "type": "string", "index": "not_analyzed" },
+            "primary": { "type": "boolean" },
+            "index": { "type": "string", "index": "not_analyzed" },
+            "relocating_node": { "type": "string", "index": "not_analyzed" },
+            "shard": { "type": "long" },
+            "node": { "type": "string", "index": "not_analyzed" }
+          }
         }
       }
     },