Add notebook tutorials

[TommyZihao]

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Motivation

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Modification

Please briefly describe what modification is made in this PR.

BC-breaking (Optional)

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Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

Checklist

Before PR:

• [ ] I have read and followed the workflow indicated in the CONTRIBUTING.md to create this PR.
• [ ] Pre-commit or linting tools indicated in CONTRIBUTING.md are used to fix the potential lint issues.
• [ ] Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• [ ] New functionalities are covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• [ ] The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• [ ] If the modification has potential influence on downstream or other related projects, this PR should be tested with some of those projects.
• [ ] CLA has been signed and all committers have signed the CLA in this PR.

[codecov[bot]]

Codecov Report

Merging #887 (7c7ffda) into main (7c90936) will decrease coverage by 0.07%. The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #887      +/-   ##
==========================================
- Coverage   84.17%   84.10%   -0.08%     
==========================================
  Files         168      168              
  Lines       10924    11013      +89     
  Branches     1673     1691      +18     
==========================================
+ Hits         9195     9262      +67     
- Misses       1374     1392      +18     
- Partials      355      359       +4     

Flag	Coverage Δ
unittests	84.10% <ø> (-0.08%)	:arrow_down:

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%)	:arrow_down:
mmocr/models/textrecog/recognizer/base.py	55.69% <0.00%> (+0.56%)	:arrow_up:
mmocr/utils/ocr.py	77.36% <0.00%> (+1.34%)	:arrow_up:
mmocr/datasets/pipelines/crop.py	96.66% <0.00%> (+5.00%)	:arrow_up:

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