Reorganize MountService IPC

Remove auto-generated AIDL files and replace them with manually edited
.java and .cpp/.h files so that binder calls can be made from either
Java or C++.

Update the makefiles to not attempt to generate the AIDL files and also
remove the old auto-generated .java files.

Put all the storage-related C++ things in libstorage so that we don't
pollute other libraries.

Change-Id: I82d1631295452709f12ff1270f36c3100e652806