RTC: Automatically detect timezone

[TheTechnician27]

Description of Changes

Automatically detects the user's timezone and DST when computing manual RTC date/time. Adds date/time information to the emulog on CDVD reset.

Rationale behind Changes

• The current manual RTC implementation requires the user to set their BIOS timezone and DST to an assumed value of GMT+0 and Summer. There's no reason for this other than as a bodge when I didn't know how to access this information in the NVM file. This automatically accounts for whatever the timezone and DST is set to in the BIOS.
• Having this information in the emulog for debugging, especially regarding RTC, could be useful in the future.

Suggested Testing Steps

• Testing timezones and DST is rough to test because there's no global option for RTC, and thus the Start BIOS feature can't see this. The easiest option is to transfer the six values from a per-game .ini file into the global one under "EmuCore". I've tested this on my end with GMT+0, GMT+2, GMT+5:45, GMT-8, (edit: now GMT-3:30), etc.
• Under the console log, the time information is in green text right after "Resetting host memory for virtual systems..." Make sure that the information comports with your setup. Timezone, DST, Date Format, and Time Format are what you have in your BIOS. System Time Basis is where PCSX2 is drawing the system time from. System time is what the system time should be on boot.

Did you use AI to help find, test, or implement this issue or feature?

No.

[TellowKrinkle]

Seems reasonable to me but I haven't tested it

[TheTechnician27]

Latest push was just to flip the order the Time Format and Date Format are printed to comport with the order found in the BIOS menu. Nothing non-trivial.

[TheTechnician27]

Latest pushes make it so that the time printed in the console matches the resulting system time. For example, the input time we send to CDVD doesn't necessarily match the RTC due to e.g. user BIOS settings (this is intentional). This was the last issue I knew of, as I initially wasn't sure whether to simply keep the input time instead of the resulting time. However, this is much more sensible and intuitive.

[JordanTheToaster]

Ich hasse es, dass Zeitzonen eine Säule der modernen Gesellschaft sind.

[SternXD]

from a very light test seems to do what is described looking at system console

[TheTechnician27]

Just added a few comments back that were destroyed accidentally in the merge conflict resolution. Nothing functional has changed.