[MM-20979] Add first implementation of the Bleve search engine (#14562)

* [MM-20979] Add first implementation of the Bleve search engine

* Fix i18n

* Migrate searchengine utils tests

* Fix linter

* Don't add allTermsQ if both termQueries and notTermQueries are empty

* Fix test that should work if user is system admin

* Modify naming according to review comments

* Abstract getIndexDir function

* Extracting bleve engine name as a constant

* Merge both Indexer interfaces into one

* Add worker stopped message

* Allow worker to be started/stopped with config change

* Use constants for index names

* Modify test order

* Fix linter

* Trying to unlock the CI

vendor/github.com/blevesearch/bleve/analysis/datetime/optional/optional.go

@@ -0,0 +1,45 @@
+//  Copyright (c) 2014 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package optional
+
+import (
+	"time"
+
+	"github.com/blevesearch/bleve/analysis"
+	"github.com/blevesearch/bleve/analysis/datetime/flexible"
+	"github.com/blevesearch/bleve/registry"
+)
+
+const Name = "dateTimeOptional"
+
+const rfc3339NoTimezone = "2006-01-02T15:04:05"
+const rfc3339NoTimezoneNoT = "2006-01-02 15:04:05"
+const rfc3339NoTime = "2006-01-02"
+
+var layouts = []string{
+	time.RFC3339Nano,
+	time.RFC3339,
+	rfc3339NoTimezone,
+	rfc3339NoTimezoneNoT,
+	rfc3339NoTime,
+}
+
+func DateTimeParserConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.DateTimeParser, error) {
+	return flexible.New(layouts), nil
+}
+
+func init() {
+	registry.RegisterDateTimeParser(Name, DateTimeParserConstructor)
+}