[FEATURE] sap.m.UploadCollection
[FEATURE] sap.m.UploadCollection

Show 'create/add' button instead of '+' according to the new
guidelines for the file upload icon

Change-Id: I96984b127d1ac3b6883f3fe6d751fd3dab8fe37c

SAP/openui5,SAP/openui5,SAP/openui5,SAP/openui5