Implement a slider in the CPU settings tab to adjust the BASE_CLOCK_RATE
up to 1,785 MHz (Switch's official maximum clock rate). Default remains
at 1,020 MHz.

This change:
- Adds UI slider and spinbox to configure_cpu.ui with range 500-1785 MHz
- Makes BASE_CLOCK_RATE dynamic by reading from settings
- Modifies WallClock to handle dynamic clock rate changes
- Updates APM controller to properly set the clock rate
- Changes clock rate settings category from Core to CPU

The user can now easily adjust the CPU clock rate to improve performance
or manage thermals and power consumption.

Signed-off-by: Zephyron <zephyron@citron-emu.org>

Allows us to directly calculate the GPU tick without double conversion to and from the host clock tick.

Previously, we were mixing the raw CPU frequency and CNTFRQ.
The raw CPU frequency (1020 MHz) should've never been used as CNTPCT (whose frequency is CNTFRQ) is the only counter available.

The precision of sleep_for and wait_for is limited to 1-1.5ms on Windows.
Using SleepForOneTick() allows us to sleep for exactly one interval of the current timer resolution.
This allows us to take advantage of systems that have a timer resolution of 0.5ms to reduce CPU overhead in the event loop.

This formats all copyright comments according to SPDX formatting guidelines.
Additionally, this resolves the remaining GPLv2 only licensed files by relicensing them to GPLv2.0-or-later.

In addition to requiring nanosecond precision, using the native clock requires that the hardware TSC has a precision greater than the emulated CPU and its clock counter.