[TVMScript] TIR Printer: Var and Type

[yelite]

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This PR:

• Adds printing function for Var and Type in TIR
• Update the traced_object_functor to require type parameter on set_dispatch for better code readability.
• Add the TracedObject variants of helper method and constructors in Doc.

This PR is in draft state because it's branched off from a pending PR #12462

Tracking issue: https://github.com/apache/tvm/issues/11912

cc @junrushao @gbonik

[Hzfengsy]

cc @junrushao Can you help to review?

[junrushao]

Let's split this PR into 2:

• The infrastructure change
• Printer to Var and Type

[yelite]

Let's split this PR into 2:

• The infrastructure change
• Printer to Var and Type

The infra change is split into #12829