Move away from import buttons in extra_footer_actions

[thibaudcolas]

Reviewing what projects out there use the extra_footer_actions block in Wagtail templates – wagtail-content-import is the only one. This is in use to display the "import" actions dropdown. here’s a screenshot from the package’s initial design, way back:

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I’d like to eventually deprecate extra_footer_actions in Wagtail, as it seems the same results could be achieved in a much more space-efficient way. We’re trying hard to make the footer actions smaller, so we have less of the form blocked by a sticky component.

For this specific package’s use case – it feels like those import actions are unlikely to be used so often that they need to be immediately accessible. They could be moved to the main actions dropdown, or even to the listings’ dropdowns next to "add child page" to make first-time imports faster. Or we can come up with a new design that’s more space-efficient.