REACH-115 Separate SaveUploader into Model layer and View layer

`BaseSaveUploader` is base class for `NWKSaveUploader` one. `BaseSaveUploaderView` isn't base for `NWKSaveUploaderView`.
`this.app.workspaceBrowser.get('workspaces')` and `this.app.get('workspaces')` aren't the same. 1) is workspaces that aren't shown as tabs but are stored in Mongo