Support for LibreTiny platform (RTL8710, BK7231 & other modules) (#3509)

Co-authored-by: Kuba Szczodrzyński <kuba@szczodrzynski.pl>
Co-authored-by: Sam Neirinck <git@samneirinck.com>
Co-authored-by: David Buezas <dbuezas@users.noreply.github.com>
Co-authored-by: Stroe Andrei Catalin <catalin2402@gmail.com>
Co-authored-by: Sam Neirinck <github@samneirinck.be>
Co-authored-by: Péter Sárközi <xmisterhu@gmail.com>
Co-authored-by: Hajo Noerenberg <hn@users.noreply.github.com>

tests/test9.1.yaml

@@ -0,0 +1,28 @@
+# Tests for rtl87xx boards using LibreTiny
+---
+wifi:
+  ssid: "ssid"
+
+rtl87xx:
+  board: generic-rtl8710bn-2mb-788k
+
+esphome:
+  name: rtl87xx-test
+
+logger:
+
+ota:
+
+captive_portal:
+
+binary_sensor:
+  - platform: gpio
+    name: Home Button
+    pin: GPIO11
+
+sensor:
+  - platform: adc
+    id: adc_sensor
+    name: ADC
+    pin: PA19
+    update_interval: 1s