Remove oneapi build

It's experimental, not supported, riddled with compiler warnings, and is generally not useful anyway.

Author: EZForever

.github/workflows/build-oneapi.yml

@@ -25,7 +25,6 @@ Server images are tagged in the format of `server-<ssl>-<avx>`.
 - `avx`: (Only) AVX instruction set is enabled. Might be useful if you are using some old CPUs that don't support AVX2.
 - `avx2`: AVX2 instruction set is enabled. This build should support most modern/recent CPUs with reasonable performance.
 - `avx512`: AVX512 base instruction set is enabled. Currently only some high-end or server-grade CPUs support this instruction set, so check your hardware specs before using this build.
-- `oneapi`: Experimental build with the Intel oneAPI compiler, inspired by ggml-org/llama.cpp#5067. Offers a ~30% speed increase (~20tok/s vs ~15tok/s) in prompt processing on my machine compared to `avx2` builds. Not updated daily.
 
 RPC server images are tagged in the format of `rpc-server-<ssl>-<avx>`. Refer to [rpc README](https://github.com/ggml-org/llama.cpp/blob/master/tools/rpc/README.md) for detailed information.