[MM-16768] Add support for Elasticsearch v7 (#12537)

* [MM-16768] Add support for Elasticsearch v7

* Fix i18n

* Adds external services tracking to the telemetry

* Rebuild elasticsearch interface mock

* Rename diagnostics keys

* Fix merge change

einterfaces/elasticsearch.go

@@ -12,6 +12,7 @@ import (
 type ElasticsearchInterface interface {
 	Start() *model.AppError
 	Stop() *model.AppError
+	GetVersion() int
 	IndexPost(post *model.Post, teamId string) *model.AppError
 	SearchPosts(channels *model.ChannelList, searchParams []*model.SearchParams, page, perPage int) ([]string, model.PostSearchMatches, *model.AppError)
 	DeletePost(post *model.Post) *model.AppError

einterfaces/mocks/ElasticsearchInterface.go

@@ -4,9 +4,12 @@
 
 package mocks
 
-import mock "github.com/stretchr/testify/mock"
-import model "github.com/mattermost/mattermost-server/model"
-import time "time"
+import (
+	time "time"
+
+	model "github.com/mattermost/mattermost-server/model"
+	mock "github.com/stretchr/testify/mock"
+)
 
 // ElasticsearchInterface is an autogenerated mock type for the ElasticsearchInterface type
 type ElasticsearchInterface struct {
@@ -77,6 +80,20 @@ func (_m *ElasticsearchInterface) DeleteUser(user *model.User) *model.AppError {
 	return r0
 }
 
+// GetVersion provides a mock function with given fields:
+func (_m *ElasticsearchInterface) GetVersion() int {
+	ret := _m.Called()
+
+	var r0 int
+	if rf, ok := ret.Get(0).(func() int); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(int)
+	}
+
+	return r0
+}
+
 // IndexChannel provides a mock function with given fields: channel
 func (_m *ElasticsearchInterface) IndexChannel(channel *model.Channel) *model.AppError {
 	ret := _m.Called(channel)