Remove kedro.extras.datasets and kedro.extras

[noklam]

NOTE: Kedro datasets are moving from kedro.extras.datasets to a separate kedro-datasets package in
kedro-plugins repository. Any changes to the dataset implementations
should be done by opening a pull request in that repository.

Description

partial #2126

Development notes

• Added kedro_datasets for testing requirements
• Update the imports to kedro_datasets in tests, doc change will be handled by Make sure all example code blocks for datasets are runnable #2287
• Remove the

Checklist

• Read the contributing guidelines
• Signed off each commit with a Developer Certificate of Origin (DCO)
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes
• Checked if this change will affect Kedro-Viz, and if so, communicated that with the Viz team

[noklam]

[noklam]

Alright I keep getting weird files push into the repo, I will just force push this and clone a new repo.

[noklam]

A separate PR to address the coverage/test problem. Noted I change coverage temporarily because we now missing some coverage as we removed the kedro.extra.datasets

[merelcht]

[deepyaman]

[deepyaman]

Maybe remove the line from https://github.com/kedro-org/kedro/blob/main/.github/PULL_REQUEST_TEMPLATE.md about datasets moving? Don't imagine people will try to add them here, if it doesn't exist.

[noklam]

@deepyaman will do in follow up datasets issues.

[noklam]

Removed the rst files and hopefully the docs build successfully.

[astrojuanlu]