There is no option to upload a document from the AccessPoint, but you can give shared folder access to certain users to copy their QVW's to it.
As for the download, this can be enabled in the QMC, while on the User Documents -> Server -> Availability tab just enable the "Download" option and choose who can download the app. Also make sure under the Systems -> QlikView Servers -> Documents tab that "Allow Document Download" is also enabled (dont forget to click apply).
There is no standard functionality like that in QV to upload a file but you could use a 3rd party product from Home - KTLabs
They have a component called KliqPlan that allows you to Smart Paste values from Excel into an Extension Object in the QV app, have the app auto reload after submitting and then download a newly calculated table in QV to Excel.