Operator customization with Taichi JIT mode

[chaoming0625]

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BrainPy currently supports operator customization with the Taichi AOT interface (see #518 #553 ). However, many features of Taichi are not supported in taichi AOT, for example, the compatibility with macOS, and other advanced features. Therefore, it is urgent to support JIT mode-based Taichi operator customization.

[Routhleck]

See braintaichi