[aot] Bind graph APIs to python and add mpm88 example

[ailzhang]

Stack from ghstack (oldest at bottom):

• -> [aot] Bind graph APIs to python and add mpm88 example #5023
• [aot] Move ArgKind as first argument in Arg class #5017
• [aot] Serialize built graph, deserialize and run. #5016

This PR supports graph builder and runner APIs in python. Note for
simplicity I've merged builder and runner in the same Python class.
Please feel free to comment if you have any suggestions.

This PR also adds a test of saving mpm88 graph in aot module, as well
as an example script to demonstrate the speed improvement (15fps ->
45fps) compared to the current taichi.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ ailzhang
❌ Ailing Zhang

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[ailzhang]

My git author setting was stale so this won't pass the CLA check. I'll close and open a new stack. Sorry for the trouble.