[feature]: Add Centerpoint configs (#92)

* Add pointpillar configs.

* Add 0075 voxel configs.

* Add configs, change to pipeline.

* Add centerpoint.

* Add 01 configs.

* Change sparse shape

* Change model config, change centerpoint detector to inherite from mvx two stage.

* Change names of configs.

* Reduce configs.

* Fix pillar config can't use bug.

* Add readme for centerpoint.

* Streamline the code in configs.

* Change readme, add nus-3d in base config

* Use seperate_head config to build seperate head, remove '[0]' in simple_test_pts

* Remove input_modality

* Change coder weights for configs.

* Change 0075 config, change order of modules in config.

* Change loss_bbox config, remove unnecessary things.

* Add cyclic_20e.py

* Rename centerhead, move centerhead,

* Change cyclic_20e

mmdet3d/models/roi_heads/bbox_heads/__init__.py

@@ -3,11 +3,10 @@ from mmdet.models.roi_heads.bbox_heads import (BBoxHead, ConvFCBBoxHead,
                                                Shared2FCBBoxHead,
                                                Shared4Conv1FCBBoxHead)
 from .h3d_bbox_head import H3DBboxHead
-from .multi_group_head import CenterHead
 from .parta2_bbox_head import PartA2BboxHead
 
 __all__ = [
     'BBoxHead', 'ConvFCBBoxHead', 'Shared2FCBBoxHead',
     'Shared4Conv1FCBBoxHead', 'DoubleConvFCBBoxHead', 'PartA2BboxHead',
-    'H3DBboxHead', 'CenterHead'
+    'H3DBboxHead'
 ]