docs: no longer provide prebuilt blas version of llama.cpp plugin

[hydai]

Explanation

We no longer provide the prebuilt OpenBLAS version of the llama.cpp plugin.

Related issue

What type of PR is this

/kind documentation

Proposed Changes

Remove related sections.

[juntao]

Hello, I am a PR summary agent on flows.network. Here are my reviews of code commits in this PR.

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Commit db7f93efe0d9397cfde22b0200b3ca4d5234918e

Key Changes:

1. Removed Prebuilt BLAS Versions: Removed references to prebuilt versions of the llama.cpp plugin with OpenBLAS support for both x86_64 and aarch64 Linux platforms.
2. Updated Installation Instructions: Modified the installation instructions in docs/start/install.md and i18n/zh/docusaurus-plugin-content-docs/current/start/install.md to specify that the installer will provide a pure CPU version of the plugin if only CPU is available, instead of an OpenBLAS version.