Fix: Wrongly generated AM wave

The AM wave gen calculation was wrong resulting is wrong frequency
components, which can be seen in the FFT and also just at looking at the
shape of the wave.

Multiple changes were done surrounding this fix.

* tools/DacValues
    * Fix: AM wave gen calculation
    * Older/wrong AM wave data replaced with newer ones. Some deleted.
    * Documentation update to show the new calculation and other general
      information added.
* Firmware
    * Now using the corrected values to generate AM.
    * AM wave now 2250 sample points at 1.5x frequency. This change is
      not part of the fix, but done to make `fc/fm` lower making it
      easier to see the AM bands in frequency domain
    * Screenshots updated
* Unittest
    * Fix: AM test break due to the higher frequency of AM wave (2nd
      change above)

Author: coderarjob

docs/images/am_wave.png

@@ -275,7 +275,7 @@ YT_TEST (am, am_wave_normal)
 
     // As AM wave slowly increases in amplitde we expect more than 10 carrier waves reaching rail to
     // rail values.
-    YT_IN_SEQUENCE (10)
+    YT_IN_SEQUENCE (5)
     {
         // 2. Then it must reach the maximum value
         YT_MUST_CALL_IN_ORDER (HAL_IO_OUT_WRITE, YT_V (ANALOG_OUTPUT_GPIO),