Remove entity info from pages on TFT

Since v3.4, the info about entity_id shown was going all the way to Nextion and then sent back in the json return, however this requires a long (100-char) global var and the way it was implemented, it was one of those per settings page, as climate should be also recorded at the same time in case the embedded climate was installed.
This was taking too much memory, so I've moved this info to a global variable (string) in ESPHome.
There is now lots of space for code cleaning (and still pending to do the same with climate entity, as it could be only a bool to inform if embedded), but this brings the functionality.

This enabled the return to global for some components, so it probably solves #1031

nspanel_eu_code/fan.txt

@@ -17,11 +17,10 @@ Page fan
                 page home
             }else
             {
-                fansetting.txt="{\"page\": \"fan\", \"component\": \"currentpage\", \"value\": \"pagechange\", \"entity\": \""+entity.txt+"\"}"
                 printh 92
                 prints "nspanelevent",0
                 printh 00
-                prints fansetting.txt,0
+                prints "{\"page\": \"fan\", \"component\": \"currentpage\", \"value\": \"pagechange\"}",0
                 printh 00
                 printh FF FF FF
             }
@@ -61,13 +60,6 @@ Variable (string) va0
         Text          : 
         Max. Text Size: 10
     
-Variable (string) entity
-    Attributes
-        ID            : 16
-        Scope         : global
-        Text          : 
-        Max. Text Size: 100
-    
 Text fan_value
     Attributes
         ID                 : 1
@@ -272,7 +264,7 @@ Button button_off
             sys0=100*fanslider.val/fanslider.maxval
             covx sys0,va0.txt,0,0
             fan_value.txt=va0.txt+"%"
-            fansetting.txt="{\"page\": \"fan\", \"key\": \"stop\", \"value\": "+va0.txt+", \"entity\": \""+entity.txt+"\"}"
+            fansetting.txt="{\"page\": \"fan\", \"key\": \"stop\", \"value\": "+va0.txt+"}"
             printh 92
             prints "localevent",0
             printh 00
@@ -353,7 +345,7 @@ Timer timer0
             sys0=100*fanslider.val/fanslider.maxval
             covx sys0,va0.txt,0,0
             fan_value.txt=va0.txt+"%"
-            fansetting.txt="{\"page\": \"fan\", \"key\": \"percentage\", \"value\": "+va0.txt+", \"entity\": \""+entity.txt+"\"}"
+            fansetting.txt="{\"page\": \"fan\", \"key\": \"percentage\", \"value\": "+va0.txt+"}"
             printh 92
             prints "localevent",0
             printh 00
@@ -363,7 +355,7 @@ Timer timer0
         
 Timer wakeup_timer
     Attributes
-        ID         : 17
+        ID         : 16
         Scope      : local
         Period (ms): 100
         Enabled    : yes