[DOCS] Add PyPI install guidance and update install command

[tlopex]

This PR updates the TVM installation documentation

[gemini-code-assist]

Code Review

This pull request adds documentation for installing Apache TVM via PyPI, including a new installation page and updates to existing guides. The review feedback correctly highlights that the standard PyPI package is CPU-only, which is a critical limitation for users of the GPU-targeting TIRx compiler. The reviewer suggests adding warnings and pointing users to CUDA-enabled wheels from TLCPack or building from source to ensure proper GPU support.

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