Remove all traces of low_cpu_mem_usage (#38792)

* remove it from all py files

* remove it from the doc

* remove it from examples

* style

* remove traces of _fast_init

* Update test_peft_integration.py

* CIs

docs/source/ko/model_doc/chameleon.md

@@ -148,7 +148,6 @@ model_id = "facebook/chameleon-7b"
 model = ChameleonForConditionalGeneration.from_pretrained(
     model_id,
     torch_dtype=torch.bfloat16,
-    low_cpu_mem_usage=True,
     attn_implementation="flash_attention_2"
 ).to(0)
 ```