Fix incorrect installation instructions (for issue #37476) (#37640)
* debugging issue 36758
* debugging issue 36758
* debugging issue 36758
* updated attn_mask type specification in _flash_attention_forward
* removed pdb
* added a blank line
* removed indentation
* update constants
* remove unnecessary files
* created installation script, modified README
* modified requirements and install.sh
* undo irrelevant changes
* removed blank line
* fixing installation guide
* modified README, python requirements, and install script
* removed tests_otuput
* modified README
* discarded installation script and python<3.13 requirement