Browser: move the browse part of the UI to a "Browser" folder

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>
Browser: factorization
 - the flickable/flow/repeater code in a new FlowList component
 - the selection code is regrouped in this new FlowList component

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>