extensionUtils: Add DISABLING and ENABLING extension states

Extensions can export asynchronous enable() and disable()
functions. To guard against re-entrancy when enabling or
disabling an extension, this commit adds two new states:
ENABLING and DISABLING which are set immediately prior
to calling enable() and disable() respectively.

This commit updates the extensions CLI and Extensions app
with new strings for these states.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2364>

subprojects/extensions-tool/src/common.h

@@ -36,6 +36,8 @@ typedef enum {
   STATE_OUT_OF_DATE,
   STATE_DOWNLOADING,
   STATE_INITIALIZED,
+  STATE_DISABLING,
+  STATE_ENABLING,
 
   STATE_UNINSTALLED = 99
 } ExtensionState;

subprojects/extensions-tool/src/main.c

@@ -43,6 +43,10 @@ extension_state_to_string (ExtensionState state)
       return "DOWNLOADING";
     case STATE_INITIALIZED:
       return "INITIALIZED";
+    case STATE_DISABLING:
+      return "DISABLING";
+    case STATE_ENABLING:
+      return "ENABLING";
     case STATE_UNINSTALLED:
       return "UNINSTALLED";
     }