Delete empty mojo python package, and prefix all python packages with mojo_

mojo/python/system/mojo_embedder.pyx

Index: mojo/python/system/mojo_embedder.pyx
diff --git a/mojo/python/system/mojo/embedder.pyx b/mojo/python/system/mojo_embedder.pyx
similarity index 90%
rename from mojo/python/system/mojo/embedder.pyx
rename to mojo/python/system/mojo_embedder.pyx
index 16ff9afce5ac351c29a70c3de804d6c915b46433..75ae38797f46c2c75df79816d408bd28b1ea271c 100644
--- a/mojo/python/system/mojo/embedder.pyx
+++ b/mojo/python/system/mojo_embedder.pyx
@@ -7,8 +7,8 @@
 from libc.stdint cimport uintptr_t
 from libcpp cimport bool
 
-from mojo import system
-from mojo import system_impl
+import mojo_system
+import mojo_system_impl
 
 cdef extern from "third_party/cython/python_export.h":
   pass
@@ -43,8 +43,8 @@ def Init():
   InitCEmbedder(scoped_ptr[PlatformSupport](
       new SimplePlatformSupport()))
   cdef MojoSystemThunks thunks = MojoMakeSystemThunks()
-  system.SetSystemThunks(<uintptr_t>(&thunks))
-  system_impl.SetSystemThunks(<uintptr_t>(&thunks))
+  mojo_system.SetSystemThunks(<uintptr_t>(&thunks))
+  mojo_system_impl.SetSystemThunks(<uintptr_t>(&thunks))
 
 def ShutdownForTest():
   return ShutdownCEmbedderForTest()