feat: add a custom storage options param

[csy1204]

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• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure to update the docs?
• Did you write any new necessary tests?

What does this PR do?

Fixes #236 (issue).

import litdata as ld

storage_options = {
    "endpoint_url": url,
    "aws_access_key_id": id,
    "aws_secret_access_key": pw,
}

s3_path = "s3://bucket/test_dataset"
dataset = ld.StreamingDataset(s3_path, storage_options=storage_options)

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[codecov]

Codecov Report

Attention: Patch coverage is 95.23810% with 1 line in your changes missing coverage. Please review.

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Additional details and impacted files

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[tchaton]

Hey @csy1204 Looks great. Could you add an example in the README ?

[csy1204]

@tchaton Thanks for your reviews.
I've added the example of this right after ✅ Stream large cloud datasets documentation. Feel free to edit my example 😃

[tchaton]

Thanks @csy1204 for your contribution ;) Feel free to continue.