Remove BetterTransformer (#2305)

* remove bettertransformer

* style

---------

Co-authored-by: Ella Charlaix <[email protected]>

Author: IlyasMoutawwakil

.github/PULL_REQUEST_TEMPLATE.md

@@ -24,9 +24,6 @@ Fixes # (issue)
 
 <!--
 For faster review, we strongly recommend you to ping the following people:
-- ONNX / ONNX Runtime : @fxmarty, @echarlaix, @JingyaHuang, @michaelbenayoun
-- ONNX Runtime Training: @JingyaHuang
-- BetterTransformer: @fxmarty
-- GPTQ, quantization: @fxmarty, @SunMarc
-- TFLite export: @michaelbenayoun
+- Exporters (ONNX/TFLite) : @echarlaix, @JingyaHuang, @michaelbenayoun, @IlyasMoutawwakil
+- GPTQ, quantization: @SunMarc, @IlyasMoutawwakil
 -->

.github/workflows/test_bettertransformer.yml

@@ -105,18 +105,6 @@
     title: "TFLite"
   title: Exporters
   isExpanded: false
-- sections:
-  - local: bettertransformer/overview
-    title: Overview
-  - sections:
-    - local: bettertransformer/tutorials/convert
-      title: Convert Transformers models to use BetterTransformer
-    - local: bettertransformer/tutorials/contribute
-      title: How to add support for new architectures?
-    title: Tutorials
-    isExpanded: false
-  title: BetterTransformer
-  isExpanded: false
 - sections:
   - local: torch_fx/overview
     title: Overview