Packaging: Increasing default for max mapped pages to 262144
Allow 'omit_norms'  on the '_all' field

The '_all' field doesn't allow to omit norms. In certain scenarios
omitting the norm values makes a lot of sense to get senseable scoring.

Closes #3734
enable delimited payload token filter

closes #3859
[DOCS] Add doc for delimited payload token filter
do not call score() twice
make term statistics accessible in scripts

term statistics can be accessed via the _shard variable.

Below is a minimal example. See documentation on details.

```

DELETE paytest

PUT paytest
{
    "mappings": {
        "test": {
            "_all": {
                "auto_boost": true,
                "enabled": true
            },
            "properties": {
                "text": {
                    "index_analyzer": "fulltext_analyzer",
                    "store": "yes",
                    "type": "string"
                }
            }
        }
    },
    "settings": {
        "analysis": {
            "analyzer": {
                "fulltext_analyzer": {
                    "filter": [
                        "my_delimited_payload_filter"
                    ],
                    "tokenizer": "whitespace",
                    "type": "custom"
                }
            },
            "filter": {
                "my_delimited_payload_filter": {
                    "delimiter": "+",
                    "encoding": "float",
                    "type": "delimited_payload_filter"
                }
            }
        },
        "index": {
            "number_of_replicas": 0,
            "number_of_shards": 1
        }
    }
}

POST paytest/test/1
{
    "text": "the+1 quick+2 brown+3 fox+4 is quick+10"
}

POST paytest/test/2
{
    "text": "the+1 quick+2 red+3 fox+4"
}

POST paytest/_refresh

POST paytest/_search
{
    "script_fields": {
       "ttf": {
          "script": "_shard[\"text\"][\"quick\"].ttf()"
       }
    }
}

POST paytest/_search
{
    "script_fields": {
       "freq": {
          "script": "_shard[\"text\"][\"quick\"].freq()"
       }
    }
}
POST paytest/test/2/_termvector
POST paytest/_search
{
    "script_fields": {
       "payloads": {
          "script": "term = _shard[\"text\"].get(\"red\",_PAYLOADS);payloads = []; for(pos : term){payloads.add(pos.payloadAsFloat(-1));} return payloads;"
       }
    }
}

POST paytest/_search
{
   "script_fields": {
      "tv": {
         "script": "_shard[\"text\"][\"quick\"].freq()"
      }
   },
   "query": {
      "function_score": {
         "functions": [
            {
               "script_score": {
                  "script": "_shard[\"text\"][\"quick\"].freq()"
               }
            }
         ]
      }
   }
}

```

closes #3772
Allow GetAliasRequest to retrieve all aliases

Results in less data being sent over the wire, as the Cat API does not
need to have the whole cluster state.

Also added matchers for hasKey() for immutable open map (I think we should
add more of those to have map style assertions).

Closes #4455