* add the test case for the UVA

* add the context load for the uva

* Add graph_sample kernel

* Add graph_sample commit

* add new commit for graph_sample

* add unsigned long long int

* delete some remarks

* add cpu version

* add cuda eids

* add cpu eids

* delete _uva

* optimize speed: emplace_back, last_layer

* add to_uva_tensor

* add cpu return_eids choice

* add gpu return_eids choice

* add cpu reindex_nodes

* add gpu reindex_nodes

* rename op and add OMP for cpu

* add incubate api

* fix the compile problem for the PADDLE_ENFORE and different device

* fix the rcom and windows compile problem

* add unittest for graph_sample_neighbors

* fix cpu unittest and unique problem

* fix uva unittest, fix cuda unique problem

* fix the windows compile problem

* fix the windows rand_r compile problem

* add correct unittest, add src_eids dispensable

* delete black

* combine uva unittest

* mv Sample_index to Sample_Index; check input shape; fix random sample func

* delete memset & cudaMemset

* fix according to PR comments

* fix rocm ci

* modify function names according to the specification

* fix windows_openblas ci

* refine annotations, fix windows unittest, add default value for uva device_id, fix bug for input nodes with empty neighbors

* fix rocm ci

* rename graph_sample_neighbors as graph_khop_sampler, add incubate api doc

* add data type

* fix conflict
Co-authored-by: Nwawltor <fangzeyang0904@hotmail.com>