metadata when loading DICOM series

[wyli]

Is your feature request related to a problem? Please describe.
the image reader ignores metadata when loading from a directory using itk:

import itk
from monai.transforms import LoadImage

loader = LoadImage(reader="ITKReader", pixel_type=itk.UC)
img, metadata = loader("tests/testing_data/CT_DICOM")
print(metadata.keys())

output:

dict_keys(['spacing', 'original_affine', 'affine', 'spatial_shape', 'original_channel_dim', 'filename_or_obj'])

Describe the solution you'd like
the metadata output should include the dicom tags available:

dict_keys(['0008|0005', '0008|0008', '0008|0012', '0008|0013', '0008|0014', '0008|0016', '0008|0018', '0008|0020', '0008|0021', '0008|0022', '0008|0023', '0008|0030', '0008|0031', '0008|0032', '0008|0033', '0008|0050', '0008|0060', '0008|0061', '0008|0070', '0008|0090', '0008|0201', '0008|1030', '0008|103e', '0008|1090', '0010|0010', '0010|0020', '0010|0030', '0010|0040', '0010|1010', '0012|0062', '0012|0063', '0018|0015', '0018|0022', '0018|0050', '0018|0060', '0018|0090', '0018|1020', '0018|1030', '0018|1100', '0018|1110', '0018|1111', '0018|1120', '0018|1130', '0018|1140', '0018|1150', '0018|1151', '0018|1152', '0018|1170', '0018|1190', '0018|1210', '0018|5100', '0020|000d', '0020|000e', '0020|0010', '0020|0011', '0020|0012', '0020|0013', '0020|0032', '0020|0037', '0020|0052', '0020|1040', '0020|1041', '0028|0002', '0028|0004', '0028|0010', '0028|0011', '0028|0030', '0028|0100', '0028|0101', '0028|0102', '0028|0103', '0028|0120', '0028|1050', '0028|1051', '0028|1052', '0028|1053', '0032|000a', '0032|000c', '0032|1030', '0032|1033', '0040|0244', '0040|0245', '0040|0254', '0040|1001', 'spacing', 'original_affine', 'affine', 'spatial_shape', 'original_channel_dim', 'filename_or_obj'])