Move page constructors to TFT

To reduce comms between ESPHome and Nextion, which could help with some sync issues found with 921600 bps.

dev/instructions_for_developers.md

@@ -0,0 +1,24 @@
+# ESPHome
+
+When a new page is opened, a script name `page_changed` (whith a parameter `page` containing a string with the page name) is called and that one will call a page specific script named `page_<page_name>`. In addition, pages with multiple pages (entitypageXX, buttonpageXX and weatherXX) will also call a generic page named `page_entitypage`, `page_buttonpage` or `page_weather` with a parameter `page_number` containing the number of the page called.
+
+If you want to execute expecific code when a page is opened, you can extend the functionality of that specific page:
+
+```yaml
+script:
+  - id: !extend page_changed
+    then:
+      # Code to run when any page is opened
+      - lambda: |-
+          static const char *const TAG = "script.page_changed (custom)";
+          ESP_LOGD(TAG, "Custom code for page changed");
+          ESP_LOGD(TAG, "This is the new page: %s", page.c_str());
+
+  - id: !extend page_buttonpage
+    then:
+      # Code to run when any buttonpage is openend
+
+- id: !extend page_buttonpage02
+    then:
+      # Code to run when buttonpage02 is opened
+```