[AMD-NPU] Remove VitisAI non-llm recipes and add links to olive-recipes

[poganesh]

Describe your changes

This PR cleans up the repository by removing the VitisAI non-LLM recipes that have been migrated to the olive-recipes
repository. Added links in the README pointing to the corresponding model configs in olive-recipes

Checklist before requesting a review

• Add unit tests for this change.
• Make sure all tests can pass.
• Update documents if necessary.
• Lint and apply fixes to your code by running lintrunner -a
• Is this a user-facing change? If yes, give a description of this change to be included in the release notes.
• Is this PR including examples changes? If yes, please remember to update example documentation in a follow-up PR.

(Optional) Issue link

[VishalX]

Looks good for non-LLM recipes. For 4 LLMs, there are Quarot / QDQ recipes available too.

• https://github.com/microsoft/olive-recipes/blob/main/deepseek-ai-DeepSeek-R1-Distill-Qwen-1.5B/aitk/deepseek_vitis_ai_config.json
• https://github.com/microsoft/olive-recipes/blob/main/microsoft-Phi-3.5-mini-instruct/aitk/phi3_5_vitis_ai_config.json
• https://github.com/microsoft/olive-recipes/blob/main/meta-llama-Llama-3.2-1B-Instruct/aitk/llama3_2_vitis_ai_config.json
• https://github.com/microsoft/olive-recipes/blob/main/Qwen-Qwen2.5-1.5B-Instruct/aitk/qwen2_5_vitis_ai_config.json

For models having Quarot / QDQ recipes, update READMEs to point to appropriate recipes based on quantization method.

[poganesh]

Looks good for non-LLM recipes. For 4 LLMs, there are Quarot / QDQ recipes available too.

• https://github.com/microsoft/olive-recipes/blob/main/deepseek-ai-DeepSeek-R1-Distill-Qwen-1.5B/aitk/deepseek_vitis_ai_config.json
• https://github.com/microsoft/olive-recipes/blob/main/microsoft-Phi-3.5-mini-instruct/aitk/phi3_5_vitis_ai_config.json
• https://github.com/microsoft/olive-recipes/blob/main/meta-llama-Llama-3.2-1B-Instruct/aitk/llama3_2_vitis_ai_config.json
• https://github.com/microsoft/olive-recipes/blob/main/Qwen-Qwen2.5-1.5B-Instruct/aitk/qwen2_5_vitis_ai_config.json

For models having Quarot / QDQ recipes, update READMEs to point to appropriate recipes based on quantization method.

@VishalX Added links in readme for the above qdq recipes as well

[VishalX]

@jambayk pls review

[VishalX]

lgtm