wordpress-seo Use WHIP to deprecate PHP 7.2 and 7.3

Context

We want to throw a notice to admins to notify we are dropping compatibility with PHP < 7.4. The date is tentatively set to July 1st, 2024, pending decisions.

This PR can be summarized in the following changelog entry:

Introduces a notice on the WordPress dashboard and the Yoast SEO dashboard to let users know we are dropping support for PHP < 7.4 starting July 1st, 2024.

We still have the class from the previous iteration as deprecated, so to avoid any conflict/confusion I introduced a new class with a slightly different name

This PR can be acceptance tested by following these steps:

Run grunt artifact to create a zip. This makes it way easier to test on different envs.
Find a way to have WP running on PHP 7.2 and 7.3.
- e.g. I was able to have a Local by Flywheel site on PHP 7.3. I'm on Linux, I know other people could not...
- otherwise there is InstaWP which seems to support PHP back to 5.6
- Switching the docker env to an older version doesn't seem to work
- you can also hack the requirement: make sure you are on PHP 7.4, change the line 139 of src/integrations/admin/unsupported-php-version-notice.php from
```
$checker->addRequirement( VersionRequirement::fromCompareString( 'php', '>=7.4' ) );
```
to
```
$checker->addRequirement( VersionRequirement::fromCompareString( 'php', '>=8.0' ) );
```
(you can do this directly after having uploaded the artifact)
upload the artifact
activate Yoast SEO
see that you get a notice on the WP dashboard and in the Yoast SEO General page:
Click on "Remind me in 4 weeks"
- you should be redirected to the WP Dashboard and the notice should be hidden
inspect the options table and set the whip_dismiss_timestamp to at least four weeks ago, e.g 1663929217.
see that you get the notice again on the WP dashboard and in the Yoast SEO General page.
Upload the artifact to a 7.4+ env and check that you don't see any notice.

[ ] Changes should be tested with the browser console open
[ ] Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
[ ] Changes should be tested on different editors (Block/Classic/Elementor/other)
[ ] Changes should be tested on different browsers
[ ] Changes should be tested on multisite

QA can test this PR by following these steps:

This PR affects the following parts of the plugin, which may require extra testing:

[ ] This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

[ ] This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

[x] I have tested this code to the best of my abilities.
[ ] During testing, I had activated all plugins that Yoast SEO provides integrations for.
[ ] I have added unit tests to verify the code works as intended.
[ ] If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
[ ] I have written this PR in accordance with my team's definition of done.
[ ] I have checked that the base branch is correctly set.

[x] No innovation project is applicable for this PR.
[ ] This PR falls under an innovation project. I have attached the innovation label.
[ ] I have added my hours to the WBSO document.

Fixes https://github.com/Yoast/roadmap/issues/398