Fix: Update general validation benchmarks

[mbenavidez-amd]

Motivation

This pull request updates the test duration tables in the docs/index.md documentation to improve clarity, provide more detailed instructions, and add missing tests. The tables are now formatted using reStructuredText list-tables, and several test durations and descriptions have been updated or expanded.

Technical Details

Documentation formatting and clarity:

• Replaced markdown tables with reStructuredText list-table format for both single-node and multi-node test duration tables, improving readability and consistency in the documentation.

Test coverage and duration updates:

• Updated estimated durations for several tests (e.g., increased AGFHC all_lvl5 from 2 hours to 6 hours, AGFHC minihpl from 3 to 4 hours, Single Node RCCL to 11 minutes, etc.), and added missing tests such as rocHPL and additional optional workloads.
• Expanded multi-node test descriptions to include more detailed instructions (e.g., specifying which bandwidth/latency tests to run for OFED, and which performance tests to run for RCCL), and added several new benchmarks (e.g., rocBLAS FP32 GEMM, rocBLAS BF16, rocBLAS INT8, Babelstream) with references to the System Validation documentation.
• Clarified optional and specialized tests.

Test Plan

Run and confirm a successful local build of the documentation.

Test Result

Local build was successful.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[rzimmer512]

PR reviewed after it was merged. No concerns.