cubicweb-brainomics #3694374 "browse" dropdown menu [validation pending]

Add a "browse" dropdown menu in the navbar, for selecting subjects using a file.

prioritynormal
typebug
done in0.9.0
load0.200
load left0.000
closed by#2889f83faa4a [component] Add a "browse" dropdown menu in the navbar, closes #3694374
patch[component] Add a "browse" dropdown menu in the navbar, closes #3694374 [applied]