goimports (#16640)

* format using `goimports -local github.com/mattermost/mattermost-server/v5 -w`

* added goimports lint check to .golangci.yml

* format using `goimports -local github.com/mattermost/mattermost-server/v5 -w` for a corner case

* make app-layers, *-mocks and store-layers for ci check

Co-authored-by: Mahmudul Haque <mahmudulhaque@protonmail.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

services/imageproxy/atmos_camo_test.go

@@ -10,11 +10,12 @@ import (
 	"net/url"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/services/httpservice"
 	"github.com/mattermost/mattermost-server/v5/utils/testutils"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func makeTestAtmosCamoProxy() *ImageProxy {

services/imageproxy/local.go

@@ -14,9 +14,10 @@ import (
 	"net/url"
 	"path/filepath"
 
+	"willnorris.com/go/imageproxy"
+
 	"github.com/mattermost/mattermost-server/v5/mlog"
 	"github.com/mattermost/mattermost-server/v5/services/httpservice"
-	"willnorris.com/go/imageproxy"
 )
 
 var imageContentTypes = []string{

services/imageproxy/local_test.go

@@ -10,11 +10,12 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/services/httpservice"
 	"github.com/mattermost/mattermost-server/v5/utils/testutils"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func makeTestLocalProxy() *ImageProxy {