Update Members section/dashboard

[ronaldbarendse]

After doing some work on the Members section (moving member properties to a Member Content App), I noticed the dashboard looks very outdated and doesn't contain much useful information:

I think we can remove the current dashboard, as there are no videos being displayed and new ones are now added on YouTube, instead of Umbraco TV.

We can replace it with the existing 'All Members' overview instead, so it's more in line with other sections (like Users and Media). Besides this, we can add other improvements like:

• Remove the 'All Members' tree node (as it's actually the parent node for all member types, showing an unfiltered overview)
• Only show the dropdown in the 'Create' button (to select the member type) when viewing all types, otherwise directly create the type selected in the tree
• Show 'Is Approved' and groups as columns in the overview
• Add filtering (similar to Users, e.g. Status, Groups) and ordering
• Possibly move member groups to an app (right top bar) to also align with the Users section?
• Allow extensible batch actions (blue bar after selecting members)

[bjarnef]

It would be great if we could streamline users and members sections. And now in Umbraco v9 where members are more consistent with users.
#4382

Some filter options and bulk actions (e.g. to approve multiple members) would also be very useful in projects with a lot of members.