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/cache/lru.go

@@ -8,10 +8,10 @@ import (
 	"sync"
 	"time"
 
-	"github.com/mattermost/mattermost-server/v5/model"
-
 	"github.com/tinylib/msgp/msgp"
 	"github.com/vmihailenco/msgpack/v5"
+
+	"github.com/mattermost/mattermost-server/v5/model"
 )
 
 // LRU is a thread-safe fixed size LRU cache.