Move HTTP service to public for plugin use (#27284)

* Move httpservice for use in plugins

* Adapt httpservice for plugin use

* Fix lint

server/channels/jobs/export_process/worker.go

@@ -9,10 +9,10 @@ import (
 	"path/filepath"
 
 	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/shared/configservice"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
 	"github.com/mattermost/mattermost/server/public/shared/request"
 	"github.com/mattermost/mattermost/server/v8/channels/jobs"
-	"github.com/mattermost/mattermost/server/v8/platform/services/configservice"
 )
 
 type AppIface interface {