Fix compile issues related to NO_ACTION_MACRO/FUNCTION and LTO_ENABLE (#8663)

* Define NO_ACTION_MACRO/FUNCTION in header instead of makefile when LTO is enabled

Currently, boards and keymaps that define NO_ACTION_MACRO/FUNCTION unconditionally
will not compile with LTO_ENABLE (#8604). This fixes the issue by moving the
definitions from common.mk to action.h, which enables us to check for previous
definitions of those macros (this cannot be done in a makefile).

* Remove LTO checks in templates

Since now NO_ACTION_MACRO/FUNCTION are defined as needed in action.h (which is
included by quantum.h), checking for LTO in keyboard and user code is no
longer required.

* Update LTO_ENABLE docs

quantum/template/avr/config.h

@@ -195,6 +195,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_MACRO
 //#define NO_ACTION_FUNCTION
 
+/* disable these deprecated features by default */
+#define NO_ACTION_MACRO
+#define NO_ACTION_FUNCTION
+
 /*
  * MIDI options
  */

quantum/template/ps2avrgb/config.h

@@ -46,7 +46,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define BACKLIGHT_LEVELS 1
 #define RGBLIGHT_ANIMATIONS
 
-#define NO_UART 1
+/* disable these deprecated features by default */
+#define NO_ACTION_MACRO
+#define NO_ACTION_FUNCTION
 
 /* key combination for magic key command */
 /* defined by default; to change, uncomment and set to the combination you want */