Use image_url from API response

[Inna-r]

issue #351

• Templates use image URLs from API
• Added directive for image URL validation
  • broken URLs are redirected
• item page and galleries should not show broken images

notes

• there are 3 types of images:
  1. digitizied image with valid and accessible image file
  2. not digitized image - physical item which doesn't have related image file
  3. (what appears like) a digitized image - but doesn't have related and accessible image file

[OriHoch]

@Inna-r some more documentation is needed / examples of the different types of items, reproduction steps etc..

[Libisch]

@OriHoch - I'll try to review the current situation, so we can decide on how to proceed with this issue. @TheGrandVizier please correct me if I'm wrong:

Currently, there are three types of pictures (Item['Pictures']) in photoUnits:
1. picture does not have a pictureId, therefore does not have a PictureUrl:
Item page, Pictures[1]:

2. picture has a PictureId, has a PictureUrl, but it's not valid:
Item page, Pictures[0]:

3. picture has a valid PictureId and there for has a valid PictureUrl:
Item page, Picture[0]:

Reproduce:

• Open item pages (1, 2, 3)
• Expected:
  Item page should present only valid photos
• Actual:
  1- Item page presents a "not yet digitized" thumbnail, link leads to a volunteering page on bh.org.il.
  2- Item page presents a broken image thumbnail and link returns ["Access denied"]
  3- Item page presents valid thumbnails and links to storage are valid.