Add and filter doc.

docs/Filter/And.md

+# And Filter
+
+> More info about and filter is in the [official elasticsearch docs][1]
+
+A filter that matches documents using the AND boolean operator on other filters.
+Can be placed within queries that accept a filter.
+
+## Simple example
+
+```JSON
+{
+    "filtered" : {
+        "query" : {
+            "term" : { "name.first" : "shay" }
+        },
+        "filter" : {
+            "and" : [
+                {
+                    "range" : {
+                        "postDate" : {
+                            "from" : "2010-03-01",
+                            "to" : "2010-04-01"
+                        }
+                    }
+                },
+                {
+                    "prefix" : { "name.second" : "ba" }
+                }
+            ]
+        }
+    }
+}
+```
+
+And now the query via DSL:
+
+```php
+$rangeFilter = new RangeFilter('postDate', ['from' => '2010-03-01', 'to' => '2010-04-01']);
+$prefixFilter = new PrefixFilter('name.second', 'ba');
+$andFilter = new AndFilter([$rangeFilter, $prefixFilter]);
+
+$termQuery = new TermQuery('name.first', 'shay');
+
+$search = new Search();
+$search->addQuery($termQuery);
+$search->addFilter($andFilter);
+
+$queryArray = $search->toArray();
+```
+
+[1]: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-and-filter.html