Add st7920 display, (#1440)

Co-authored-by: Oxan van Leeuwen <oxan@oxanvanleeuwen.nl>
Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

tests/test1.yaml

@@ -2038,6 +2038,14 @@ display:
     backlight_pin: GPIO4
     lambda: |-
       it.rectangle(0, 0, it.get_width(), it.get_height());
+  - platform: st7920
+    width: 128
+    height: 64
+    cs_pin:
+      number: GPIO23
+      inverted: true
+    lambda: |-
+      it.rectangle(0, 0, it.get_width(), it.get_height());
   - platform: st7735
     model: 'INITR_BLACKTAB'
     cs_pin: GPIO5