rl [Feature] Crop Transform

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

Why is this change required? What problem does it solve? If it fixes an open issue, please link to the issue here. You can use the syntax close #15213 if this solves the issue #15213

[ ] I have raised an issue to propose this change (required for new features and bug fixes)

Types of changes

What types of changes does your code introduce? Remove all that do not apply:

[ ] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds core functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to change)
[x] Documentation (update in the documentation)
[ ] Example (update in the folder of examples)

Checklist

Go over all the following points, and put an x in all the boxes that apply. If you are unsure about any of these, don't hesitate to ask. We are here to help!

[ ] I have read the CONTRIBUTION guide (required)
[ ] My change requires a change to the documentation.
[ ] I have updated the tests accordingly (required for a bug fix or a new feature).
[ ] I have updated the documentation accordingly.

Jul 30 '24 10:07 albertbou92

:link: Helpful Links

:test_tube: See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/rl/2336

:page_facing_up: Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

:x: 4 New Failures, 14 Unrelated Failures

As of commit 07e4e1a5cdc93e6ae0685f351c0b7ed14a4ecf49 with merge base 0063741839a3e5e1a527947945494d54f91bc629 ():

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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Jul 30 '24 10:07 pytorch-bot[bot]

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

Jul 30 '24 13:07 albertbou92