Rework container management

* based on liblxc now
* container is managed by a management process which needs to run as
  root. LXC will take care of strict confinement of this container.
  We still don't allow any direct hardware access.
* `anbox shell` command is gone. Same functionality can be archive
  with the lxc-attach command.

src/container_main.cpp

@@ -15,8 +15,12 @@
  *
  */
 
-extern "C" int bwrap_main(int argc, char **argv);
+#include "anbox/container/service.h"
 
 int main(int argc, char **argv) {
-    return bwrap_main(argc, argv);
+    (void) argc;
+    (void) argv;
+    anbox::container::Service service;
+
+    return 0;
 }