lawl we totally forgot to put dataset renaming back in

[b5]

So while we're here, might as well make renaming work properly.

I think we should add it as a text-link next to remove in the dataset action buttons, the link text should be in blue, not in red.

• It should present a modal that says "choose a new dataset name"
• the modal should display the current dataset name
• the modal should show validation errors when the name is invalid.
• the modal should have a cancel "x" (or a cancel button, whatever's easier)
• The save button should flip to "loading" when the user hits submit, and the modal should dismiss on successful change
• the user should see a message that says "dataset successfully renamed"
• the user should be redirected back to the collections page