[PY] GraphRuntime: Update the tutorials to the module-based interface (#6482)

[PY] GraphRuntime: Update the tutorials to the module-based interface (#6482)

* [PY] GraphRuntime: Update the tutorials to the module-based interface.

Also added document about the encouraged usage.
In particular, we encourage the following usage.

lib = relay.build(...)
gmod = graph_runtime.GraphModule(lib["default"](ctx))

I have changed most of the tutorials and apps.
Some follow up PRs are needed to update some of the tests code.

* Fix VTA tutorials