chore: remove support for IE 9 and IE 10

[DanielRuf]

Description

IE 9 and IE 10 are quite old and there is no support from MS anymore. Just IE 11 is supported until 2025.

Also we explicitely mention that we only support IE 11 and Edge, see https://devdocs.magento.com/guides/v2.0/install-gde/system-requirements_browsers.html and https://devdocs.magento.com/guides/v2.3/install-gde/system-requirements_browsers.html

Fixed Issues (if relevant)

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Manual testing scenarios

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Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @DanielRuf. Thank you for your contribution
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[miguelbalparda]

Very interesting PR, can you please check the failing tests while I check what the consensus on this one is?

[DanielRuf]

can you please check the failing tests

Done.
https://travis-ci.org/magento/magento2/jobs/411618035#L1090

[BenGlassAtlas]

+1 The CSS for M2 never fully loaded in IE9 anyway so it makes a lot of sense to remove it - #5126

[magento-engcom-team]

Hi @miguelbalparda, thank you for the review.
ENGCOM-2678 has been created to process this Pull Request

[magento-engcom-team]

Hi @DanielRuf. 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.