v1.14.0: Medicine stock tracking

[Futsch1]

A long awaited and much requested feature has been added in v1.14.0: Tracking of medicine stock. For this, a new icon was added to the medicine view (the box):

For each medicine, the amount in stock can be set, a potential reminder can be setup and a convenient refill button increases the amount by a configurable pack size. These reminder appear as soon as the stock level has reached the indicated threshold. Medicine stock levels are also shown in standard reminders and in the medicine list.

Significant changes were made under the hood to make automatic testing much more stable and reducing multi-threading complexity.