APP_Framework/Framework/:update knowing framework

1.fix some Kconfig file
2.add tensorflow-lite-for-mcu in knowing file
3.add mnist application,note the application cannot be used with RAM less than 500K.
4.the version need to separate application and OS(rtt),later by using add transform layer to solve it.

APP_Framework/Applications/knowing_app/SConscript

@@ -0,0 +1,14 @@
+import os
+Import('RTT_ROOT')
+from building import *
+
+cwd = GetCurrentDir()
+objs = []
+list = os.listdir(cwd)
+
+for d in list:
+    path = os.path.join(cwd, d)
+    if os.path.isfile(os.path.join(path, 'SConscript')):
+        objs = objs + SConscript(os.path.join(path, 'SConscript'))
+
+Return('objs')