Added "RESOLUTION" parameter

Discord User jteich did some investigation (Thanks!) and helped me understanding this rather obscure parameter:

Internally, is called "TRIGGER", and is passed into the baseband when configuring the desired spectrum sample rate.

Please forgive me in advance if this explanation is not 100% correct. It's only my interpretation, based on my own observation and jteich's comments over Discord chat.

This trigger parameter apparently determines the amount of data over time used for calculating the signal's power inside each specttrum's bin, before considering it "done".

In short, if you lower this resolution value then the cascade will tend to be rendered a bit faster, while kind of blind to tiny signals.

On the other hand, a bigger value will help rendering and distinguishing different signals on the cascade.

Too big a value can easily clutter up the cascade. But then it may be a "blessing" when inspecting higher freuqencies -where hackrf is more deaf"

The default value of 32 is quite decent. But then, now you can experiment with it. Cheers

firmware/application/apps/ui_looking_glass_app.hpp

@@ -89,8 +89,8 @@
             {{0, 0}, "MIN:     MAX:     LNA   VGA  ", Color::light_grey()},
             {{0, 1 * 16}, " RANGE:     FILTER:      AMP:", Color::light_grey()},
             {{0, 2 * 16}, "PRESET:", Color::light_grey()},
-            {{0, 3 * 16}, "MARKER:     MHz +/-    MHz", Color::light_grey()}
-
+            {{0, 3 * 16}, "MARKER:     MHz +/-    MHz", Color::light_grey()},
+             {{0, 4 * 16}, "RESOLUTION:    (fft trigger)", Color::light_grey()}
         };
 
          NumberField field_frequency_min {
@@ -151,6 +151,14 @@
             {20 * 8, 3 * 16, 2 * 8, 16},
             ""};
 
+        NumberField field_trigger{
+             {11 * 8, 4 * 16},
+             3,
+             {2, 128},
+             2,
+             ' '};
+
+
      MessageHandlerRegistration message_handler_spectrum_config {
  		Message::ID::ChannelSpectrumConfig,
  		[this](const Message* const p) {