T-Echo screen and button performance (#3840)

* Make button timing configurable per variant

* Adjust button timing for T-Echo
Easier multi-clicks for features like "toggle backlight" (4x click)

* Fewer full-refreshes for T-Echo display
Disables ghost pixel tracking: T-Echo ghost pixels are fairly faint.

variants/t-echo/platformio.ini

@@ -15,7 +15,7 @@ build_flags = ${nrf52840_base.build_flags} -Ivariants/t-echo
   -DEINK_LIMIT_FASTREFRESH=20          ; How many consecutive fast-refreshes are permitted
   -DEINK_LIMIT_RATE_BACKGROUND_SEC=30  ; Minimum interval between BACKGROUND updates
   -DEINK_LIMIT_RATE_RESPONSIVE_SEC=1   ; Minimum interval between RESPONSIVE updates
-  -DEINK_LIMIT_GHOSTING_PX=2000        ; (Optional) How much image ghosting is tolerated
+;   -DEINK_LIMIT_GHOSTING_PX=2000        ; (Optional) How much image ghosting is tolerated
   -DEINK_BACKGROUND_USES_FAST          ; (Optional) Use FAST refresh for both BACKGROUND and RESPONSIVE, until a limit is reached.
 build_src_filter = ${nrf52_base.build_src_filter} +<../variants/t-echo>
 lib_deps = 

variants/t-echo/variant.h

@@ -65,6 +65,9 @@ extern "C" {
 #define PIN_BUTTON2 (0 + 18)      // 0.18 is labeled on the board as RESET but we configure it in the bootloader as a regular GPIO
 #define PIN_BUTTON_TOUCH (0 + 11) // 0.11 is the soft touch button on T-Echo
 
+#define BUTTON_CLICK_MS 400
+#define BUTTON_TOUCH_MS 200
+
 /*
  * Analog pins
  */