v1.0.15: Default TX power to board PA_MAX_OUTPUT

- Add PA_MAX_OUTPUT define: V3=22, V4=28, default=20
- Captive portal TX power field now defaults to board max

Boards.h

@@ -379,6 +379,8 @@
       #define HAS_BUSY true
       #define DIO2_AS_RF_SWITCH true
 
+      #define PA_MAX_OUTPUT  22
+
       // Following pins are for the SX1262
       const int pin_cs = 8;
       const int pin_busy = 13;
@@ -935,6 +937,10 @@
     #define OCP_TUNED 0x18
   #endif
 
+  #ifndef PA_MAX_OUTPUT
+    #define PA_MAX_OUTPUT 20
+  #endif
+
   #ifndef NP_M
     #define NP_M 0.15
   #endif