Search by group name

**Is your feature request related to a problem? Please describe.**
On my desktop I use the classic KeePass (Windows) and often search for results by group name.
I have hundreds of items in the database, so it's not possible to efficiently search just by name or URL etc.

**Describe the solution you'd like**
I would like to be able to search by group name. This could be placed here:

**Additional context**
At first glance a bit similar to https://github.com/Kunzisoft/KeePassDX/issues/1734 but this is not the same

The issue names no source files or tests; start by locating the existing search entry point and reviewing issue 1734 for related context. Done means users can search entries by their KeePass group name, with the search option available in the requested location and behavior covered by appropriate tests.

Written by the indexing model from the issue text.