v1.9.3: Menu rework and activating/deactivating all reminders

[Futsch1]

To implement the feature request that a medicine can be activated or deactivated completely, a rework of the context menu system was required. Previously, the menu icon on the top left always contained the same menu items. This menu is now only visible on the three main pages (Overview, Medicine and Analysis). Other pages would now either contain no menu or one that adds specific action for the page.

This menu can now be used to delete a reminder or a medicine, at the same time, the option to do this via long press was removed. So deletion can now be done via swipe or context menu.

When selecting a medicine, the context menu can now be used to activate or deactivate all reminders of a medicine with one click. This makes it possible to easily deactivate a medicine temporarily. This is also shown in the medicines list.