* Part 1 for #3067: Basic combo box (dropdown) filtering mechanism for game age.
* Apply suggestions from draft review
# Conflicts:
# cockatrice/src/gamesmodel.cpp
# cockatrice/src/gamesmodel.h
* switch to using QTime
* check for games older than a day
* formatting for casts and more unnecessary cosmetic changes
* ebbit1q fixes
Co-authored-by: ebbit1q <ebbit1q@gmail.com>