[Forwardport]Delete all unused imports of lib/internal/Magento

[VitaliyBoyko]

Description

Deleted Manually all imports not used inside lib/internal/Magento that not needed
Original PR: #16946

PS. Some imports are already fixed so this PR contain fewer changes then the original one.

[magento-engcom-team]

Hi @VitaliyBoyko. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
Add the comment under your pull request to deploy test or vanilla Magento instance:

• @magento-engcom-team give me test instance - deploy test instance based on PR changes
• @magento-engcom-team give me {$VERSION} instance - deploy vanilla Magento instance

For more details, please, review the Magento Contributor Assistant documentation

[magento-engcom-team]

Hi @VitaliyBoyko. Thank you for your contribution.
We will aim to release these changes as part of 2.3.0.
Please check the release notes for final confirmation.