macOS: Import notarization credentials

Imports apple notarization credentials (Apple ID and App-specific password) given to cmake as `-DNOTARY:STRING="-u woz@apple.com -p abcd-efgh-ijkl-mnop"`

CMakeLists.txt

@@ -256,6 +256,10 @@ if(APPLE)
     if("${CODESIGNID}")
         set(CODESIGNID "${CODESIGNID}" CACHE STRING "Codesigning Identity")
     endif()
+    if("${NOTARY}")
+        set(NOTARY "${NOTARY}" CACHE STRING "Notarization Identity")
+    endif()
+
 endif()
 
 # Enforce absolute paths for non-bundle builds: