[REF] html_editor, *: dialog plugin

[FrancoisGe]

The purpose of this commit is to add a dialog plugin that will centralise the behaviour shared between dialogs opened from the editor. The behaviour shared by all the editor dialogs is the repositioning of the selection in the editable when a dialog closes.

Description of the issue/feature this PR addresses:

Current behavior before PR:

Desired behavior after PR is merged:

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I confirm I have signed the CLA and read the PR guidelines at www.odoo.com/submit-pr

[robodoo]

[Goaman]

robodoo r+

[robodoo]

@FrancoisGe @goaman linked pull request(s) odoo/enterprise#71040 not ready. Linked PRs are not staged until all of them are ready.

[Goaman]

robodoo r+