mini-widgets-bar: allow viewing and setting name

Mini-widget container "bars" are currently automatically given the name of a random ocean animal when they get created, but there's no indication of what the name is for a given container, and there's no way to change the names.

I think in edit mode the bars should have visible names, and configuring a bar from the regular widgets edit menu should allow changing the name to something custom.

Start by tracing the mini-widgets-bar implementation and the regular widgets edit menu to find where bars are created, displayed in edit mode, and configured. Done means each bar visibly shows its current name in edit mode and its configuration allows replacing that name with custom text.

Written by the indexing model from the issue text.