* refactor: add StatsMode to libtransmission-app
* test: add display-mode unit tests
* feat: add apicompat for StatsMode
* refactor: use StatsMode in Qt client
* refactor: add template method for gtr_set_pref()
* refactor: use StatsMode in GTK client
* ci: use the all-tests alias instead of hardcoding tests
* ci: copy runtime DLLS into test output directory for Windows test binaries