MSP Multiple GYRO/ACC alignment support

* Make use of 1.41.0 MSP API changes introduced
  https://github.com/betaflight/betaflight/pull/7506
* Not really happy with the elements/css, but opening this up for feedback. I
  can't quite get the select inputs or the text/icons to go where I want :p

src/js/fc.js

@@ -336,6 +336,10 @@ var FC = {
             align_gyro:                 0,
             align_acc:                  0,
             align_mag:                  0,
+            use_multi_gyro:             0,
+            gyro_to_use:                0,
+            gyro_1_align:               0,
+            gyro_2_align:               0,
         };
 
         PID_ADVANCED_CONFIG = {