settings: Add custom RTC settings

Stored as signed seconds since epoch.

src/yuzu_cmd/default_ini.h

@@ -183,6 +183,12 @@ enable_nfc =
 rng_seed_enabled =
 rng_seed =
 
+# Sets the current time (in seconds since 12:00 AM Jan 1, 1970) that will be used by the time service
+# This will auto-increment, with the time set being the time the game is started
+# This override will only occur if custom_rtc_enabled is true, otherwise the current time is used
+custom_rtc_enabled = 
+custom_rtc = 
+
 # Sets the account username, max length is 32 characters
 # yuzu (default)
 username = yuzu