Using templates in JS

[rgaudin]

Instead of building all the UI elements within JS code, we now have a few templates:

• display_rows that renders the main list of items
• media_player that renders the popup content with the files
• modal_title that renders the modal title
• modal_empty_body for when modal is displayed until content appears.

Use of the templates allowed to tackle:

• 13: french strings removed from JS. Only one string remains. It is now passed

  as an i18n option from the HTML. Not ideal but good enough until we need more.

• 11: if the item has multiple files, display a folder icon instead of first item's

  extension one. Makes more sense and required by items with multiple formats. Opens the modal player.

• 2 audio/video extensions has been added and template now conditionnally displays

  a <video /> or <audio /> tag.

Also:

• updated zimwriterfs to 1.3.9 in docker image