Migrate functions to app package (#5106)

* Refactor and move session logic into app package

* Refactor email functions into the app package

* Refactor password update into app package

* Migrate user functions to app package

* Move team functions into app package

* Migrate channel functions into app package

* Pass SiteURL through to app functions

* Update based on feedback

api/file.go

@@ -46,8 +46,6 @@ const (
 	RotatedCCW         = 6
 	RotatedCCWMirrored = 7
 	RotatedCW          = 8
-
-	MaxImageSize = 6048 * 4032 // 24 megapixels, roughly 36MB as a raw image
 )
 
 func InitFile() {
@@ -162,7 +160,7 @@ func doUploadFile(teamId string, channelId string, userId string, rawFilename st
 
 	if info.IsImage() {
 		// Check dimensions before loading the whole thing into memory later on
-		if info.Width*info.Height > MaxImageSize {
+		if info.Width*info.Height > model.MaxImageSize {
 			err := model.NewLocAppError("uploadFile", "api.file.upload_file.large_image.app_error", map[string]interface{}{"Filename": filename}, "")
 			err.StatusCode = http.StatusBadRequest
 			return nil, err