Quickly open entry search by pulling/swiping down

**Is your feature request related to a problem? Please describe.**
When I want to open the search I need to click on the icon on the top right corner on my phone (which is not that small and not that easy to reach).

**Describe the solution you'd like**
The solution I'd like would be a function for quickly opening the search by a gesture by doing a swipe downwards. This of course should only work if you already are on top of the entry list so that the swipe/pull down does not come into conflict with the normal scrolling of the entries.

**Describe alternatives you've considered**
Alternatively there could be a function to move the search button down to the bottom of the device to the "add new entry" for example, so that it's easier to reach with the thumb.

No files or tests are named. Start by locating the Android entry-list screen, its search action, and existing swipe or refresh handling. Done means a downward swipe while already at the top opens entry search without disrupting normal list scrolling; verify the behavior on a phone.

Written by the indexing model from the issue text.