[Enhancement] Support different seeds on different ranks

[gaotongxiao]

... which diversifies the seeds and improves the randomness.

Ref

open-mmlab/mmselfsup#228
https://github.com/open-mmlab/mmtracking/pull/455/files

[codecov]

Codecov Report

Merging #820 (601cf24) into main (402e8f1) will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #820      +/-   ##
==========================================
- Coverage   84.35%   84.27%   -0.09%     
==========================================
  Files         166      166              
  Lines       10745    10745              
  Branches     1637     1637              
==========================================
- Hits         9064     9055       -9     
- Misses       1335     1343       +8     
- Partials      346      347       +1     

Flag	Coverage Δ
unittests	84.27% <ø> (-0.09%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmocr/datasets/pipelines/transforms.py	82.56% <0.00%> (-1.43%)	⬇️

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