Enhancement: Respect share max, min and enforced expiration date

if the expiration date max and/or enforcement is supported (defined by the capabilities) the UI now handles the different cases and respects the backend settings.
In oc10 there are options to enforce the maximum available date for group and user shares, this is now considered in the UI and updates dynamically in both cases.

https://github.com/owncloud/web/pull/6176
https://github.com/owncloud/web/pull/6039
