implement shelves visibility

[maxlath]

The client side of inventaire/inventaire#624

The trickiest bit was definitely the VisibilitySelector component and its inference system. Some examples:

• if visibility = [ 'public' ] then checked = [ 'public', 'friends', 'groups', 'group:a', 'group:b' ]
• if visibility = [ 'groups ] then checked = [ 'groups', 'group:a', 'group:b' ]
• if group:a is unchecked, then both public and groups should be removed from the visibility array
  The good news is that this component should be straight forward to reuse for other document types (items, lists)

[jum-s]

the more i use this new visibility selector, the more a "private" checkbox makes sense to me. It would then be an explicit choice, instead of the currently implicit of not having any checkbox checked

could be v2, but i can dig into it

[maxlath]

The problem with a "private" checkbox is that it breaks the selectors logic. The same purpose could be done without this inconvenient by haveing a "you" checkbox, which can not be unchecked, so that when you uncheck everything else, the only visibility remaining is "you". I would be in favor of shipping the current implementation and see the user feedback we get

[maxlath]

Moreover, when every box is unchecked, the displayed selected value is "private", confirming what the user might have guessed

[jum-s]

your last comment is largely depending of the information displayed by the consumer of the visibility selector, hence the user might not see "private" every time a selector is displayed