Release Distribution base class and Normal, Uniform class (#26355)

* fixed static module

* solve conflict

* Add Distribution base class, Uniform class and Normal class

* release Distribution class and Normal, Uniform class

* Add Doc args explaination

* save distributions.py and process in distribution.py

* delete useless function in test_distribution

* Add NormalNumpy test class

* Add probs in NormalNumpy

* add distribution to paddle init

* Add Distribution base class and name attribute unittest

* Change Doc

* Change Doc

* adjust format

* Fixed Doc Code

* implement probs and change Variable to Tensor

* Add name for all functions and add name unittest

* support int datatype

* Add dynamic mode

* optimize test_distribution static and dygraph

python/paddle/__init__.py

@@ -38,6 +38,7 @@ import paddle.compat
 import paddle.distributed
 import paddle.sysconfig
 import paddle.tensor
+import paddle.distribution
 import paddle.nn
 import paddle.distributed.fleet
 import paddle.optimizer