[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/size/sizes.go

@@ -0,0 +1,59 @@
+//  Copyright (c) 2018 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 size
+
+import (
+	"reflect"
+)
+
+func init() {
+	var b bool
+	SizeOfBool = int(reflect.TypeOf(b).Size())
+	var f32 float32
+	SizeOfFloat32 = int(reflect.TypeOf(f32).Size())
+	var f64 float64
+	SizeOfFloat64 = int(reflect.TypeOf(f64).Size())
+	var i int
+	SizeOfInt = int(reflect.TypeOf(i).Size())
+	var m map[int]int
+	SizeOfMap = int(reflect.TypeOf(m).Size())
+	var ptr *int
+	SizeOfPtr = int(reflect.TypeOf(ptr).Size())
+	var slice []int
+	SizeOfSlice = int(reflect.TypeOf(slice).Size())
+	var str string
+	SizeOfString = int(reflect.TypeOf(str).Size())
+	var u8 uint8
+	SizeOfUint8 = int(reflect.TypeOf(u8).Size())
+	var u16 uint16
+	SizeOfUint16 = int(reflect.TypeOf(u16).Size())
+	var u32 uint32
+	SizeOfUint32 = int(reflect.TypeOf(u32).Size())
+	var u64 uint64
+	SizeOfUint64 = int(reflect.TypeOf(u64).Size())
+}
+
+var SizeOfBool int
+var SizeOfFloat32 int
+var SizeOfFloat64 int
+var SizeOfInt int
+var SizeOfMap int
+var SizeOfPtr int
+var SizeOfSlice int
+var SizeOfString int
+var SizeOfUint8 int
+var SizeOfUint16 int
+var SizeOfUint32 int
+var SizeOfUint64 int