* add spaceinvaders multi gpu

* add dp and ddp

* Update __init__.py

* recover init

* added experience replay and n-step

* implementing distributional q value

* added distributional q-value

* added overview in qac_dist and d4pg

* derived D4PG from DDPG

* fixed a bug when action shape >1

* benchmark D4PG mujoco + minor fixs

-entry for DDPG mujoco
-entry for D4PG mujoco
-config for D4PG mujoco
-fixed style D4PG code
-unittests for QAC distributional

* formatted code

* minor updates (read description)

-added d4pg seria_entry test
-updated comments in QACDIST
-added d4pg in commander register
-added q_value in d4pg return dict
-added priority update in d4pg entry
-added assertion in QACDIST

* feature(nyz): add resnet for cv sl task

* feature(nyz): add imagenet classification dataset and adapt compile config for sl

* feature(nyz): add naive image training entry demo

* style(nyz): polish image cls train log

* polish(nyz): polish multi gpu training setting

* feature(nyz): add nn training bp and update async execution

* feature(nyz): add distributed sampler for different dist backend

* fix(nyz): fix compile config collector and buffer compatibility problem

* style(nyz): correct yapf format

* fix(nyz): fix env manager compile config compatibility bug

* refactor(nyz): abstarct ISerialEvaluator and rename serial evaluation implementation

* refactor(nyz): refactor collector name

* feature(nyz): add metric evaluator and image cls acc metric eval demo

* fix(nyz): fix cuda and multi gpu bug in image cls demo