Final UX pass on Sidebar / Gallery / Diffs

[YousefED]

Apply feedback from https://docs.numerique.gouv.fr/docs/12715032-d314-4d0a-9002-a92a343b712e/,

but let's first align on the product requirements for the sidebar (blocked by #88)

• don't show create link as popup for a link attribute change (when it might have been modified / removed)
• Remove tabs. Instead, add a "Named versions only" button / toggle that filters the list
• Make the ... menu extensible, so consumers can add functionality like "Make a copy"
• Add a "Name this version" option to the ... menu for unnamed versions. And "Rename" for named ones. Clicking should put the "name" in edit mode
• When the panel opens, editing should be disabled.
• When the panel opens, the latest version should be selected by default. The latest version should always contain the latest edits
• When the panel opens, we should make sure no new edits from other collaborators are displayed
• It should not be possible to not select a version (including in the type system)
• Add a (configurable?) loading state when changing versions / opening the panel
• Make it clearer versions can be renamed: Caret-cursor-on-hover, border / outline on click
• Make the panel fully accessible (possibly, Matthew can help with this
• An option should exist that we scroll to the first Diff when changing a version / compare
• Remove the "save" button
• Dates should always show the "last edit time" of a version
• Swap to use "trailing" (end) activity items as discussed

Diffs:

• Unnecessary padding between attribution data and titles and other element etc.
• Color palet used to attribute changes of users should avoid shades of green and red. So users don't think red are deletions and green additions