- replace the node breadcrumb link with a SeedPicker in the repo, user
and node views, so the node serving a page can be switched where it
is named
- remove current node picker from settings panel
- reach the node view through the picker's "Open node view" action
- cover the new breadcrumb picker in the e2e tests
- list the active seed in the seed picker
- the seed serving the page is also rendered in the list with a bookmark
action instead of a remove one.
Picking a seed only set the stored preference and left the page on
whatever node the URL named, so the node could not be changed from
the UI at all. The two are now independent: you can browse a repo
on one node while searching a larger index on another.