images section: implement some javascript-based image browser/gallery

[j3nda]

problem:

• in images section is missing some comfortable image browsing, eg:
• smaller thumbnails (~configurable)
• fullscreen image browsing (all galery)
• download, @see: images section: download files as .zip #1

solution:

• do some research, which javascript image/gallery browser is easiest to implement (idealy not so much css and js files and/or dependency to another js-libraries. definitely not composer or npm) - KISS !!!
• implement this broser
• make it little bit configurable (if its possible)

note:

• im looking at our press-kit, here: http://press.straitjacket-entertainment.com/planet-gula/ (and im missing this feature now)