* move variable_utils from phi_api_utils to fluid

* fix coment

* update include

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* update

* update

* fix CI-Windows-OpenBLAS

* fix bugs

* fix bugs

* fix bugs

* update include

* move variable_utils to phi_utils

* fix namespace

* rename pten dir to phi

* rename namespace to phi

* rename infrt pten dir to phi

* resolve conflict

* rename pten to phi in cmake

* revert all infrt change

* change needed files

* fix infrt failed

* fix inference failed

* open header for custom kernel

* add core utils

* tidy core code

* tify header

* tidy include

* tidy namespace

* resolve conflit

* fix unittest and coverage

* remove platform using

* resolve conflict

* resolve conflict

* fix digamma namespace error

* fix xpu full kernel error

* fix xpu full kernel error

* polish details

* add place for lib storage