(ui): allow to delete series from the selection view from a button

Description

Add buttons to each row af SSelector to delete the related study/serie.

Closes #630 (closed)

I'm not really proud of this version, if anyone has a better idea to improve the UI, i'm here to do it.

How to test it?

• Launch 'OgreViewer'.
• Go to the PACS selector.
• Retreive series from a PACS.
• Try to delete study/serie.

Some results