[TVMScript] Introduce PrinterConfig

[junrushao]

This PR introduces PrinterConfig, a systematic way to configure
TVMScript printer without having to set global flags.

This PR enables more customization of printer behavior. More
specifically, now any TVM’s object in python, as long as it
inherits from Scriptable, it automatically gains two methods:

• .script(tir_prefix=...)
• .show(...)

[tvm-bot]

Thanks for contributing to TVM! Please refer to the contributing guidelines https://tvm.apache.org/docs/contribute/ for useful information and tips. Please request code reviews from Reviewers by @-ing them in a comment.

• No users to tag found in teams: tvmscript _{See #10317 for details}

_{Generated by tvm-bot}

[Mousius]

@junrushao was this meant for unity? it contains several references to relax in the code introduced. This PR wasn't left open for much time else it might've been caught during review, it would've been good to leave such a large change open a while longer. Could you please follow up and remove the relax references?

[tqchen]

Thanks for getting to this thread. I think the particular set of changes won;'t cause technical debt that breaks the any code in the current mainline

But if there is a strong desire to remove(which i think is a nit TBH), we can do a followup PR.