[Feature] Crop Transform

[albertbou92]

Description

Currently TorchRL has a CenterCrop transform. I have recently encountered a situation were I did not want to crop the center, but another part of the obs image.
For cases like this one, it would be interesting to have a Crop transform too, that allows to define the specific location of the cropping.

This super simple PR adds it. For the tests I have pretty much used the same as CenterCrop, as it is simply a more general Transform where the cropping location can be modified.

I thought about simply having single Transform for both cases (e.g. default behaviour is center crop but the starting location can be optionally provided). However, imo it is cleaner and more intuitive to have both.

Motivation and Context

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You can use the syntax close #15213 if this solves the issue #15213

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• Breaking change (fix or feature that would cause existing functionality to change)
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❌ 4 New Failures, 14 Unrelated Failures

As of commit 07e4e1a with merge base 0063741 ():

NEW FAILURES - The following jobs have failed:

• Continuous Benchmark (PR) / CPU Pytest benchmark (gh)
  Workflow failed! Resource not accessible by integration
• Continuous Benchmark (PR) / GPU Pytest benchmark (gh)
  Workflow failed! Resource not accessible by integration
• Generate documentation / build-docs (3.9, 12.1) / linux-job (gh)
  No files were found with the provided path: /home/ec2-user/actions-runner/_work/_temp/artifacts/. No artifacts will be uploaded.
• Unit-tests on Windows / unittests-cpu / windows-job (gh)
  The process 'C:\Program Files\Git\cmd\git.exe' failed with exit code 128

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• Examples Tests on Linux / tests (3.9, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Habitat Tests on Linux / tests (3.9, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Libs Tests on Linux / unittests-gym (3.9, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Libs Tests on Linux / unittests-sklearn (3.9, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• RLHF Tests on Linux / unittests (3.9, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-cpu (3.10) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-cpu (3.11) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-cpu (3.12) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-cpu (3.8) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-cpu (3.9) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-gpu (3.11, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-olddeps (3.8, 11.6) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-optdeps (3.10, 12.1) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128
• Unit-tests on Linux / tests-stable-gpu (3.10, 11.8) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128

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[vmoens]

LGTM, just a couple of minor issues
Thanks for this!

[albertbou92]

Thanks a lot for the quick review!! I fixed the issues