implement Bazaar UI fully clickable

[brenzi]

context

Encointer bazaar is briefly introduced here: https://book.encointer.org/bazaar.html
@anizeani is working on a read-only Web UI to browse Bazaar contents by community and by shop.

This task shall build the Bazaar UI into our flutter app including composing new classifieds, new shops and possibly managing write permissions to put,modify, delete classifieds

UX design

The wireframe clickable prototype:
https://www.sketch.com/s/25ce4520-f5dc-4756-970a-7ec71733e64d/a/p9l7Op

The bazaar MVP is already done, but currently deactivated and possibly outdated:
https://github.com/encointer/encointer-wallet-flutter/tree/master/lib/page-encointer/bazaar

task scope

Please test and update all the "MVP" views and implement the "later" views.

views:

• [MVP] Home
  • [MVP] new (all shops and articles)
  • [later] shops in vicinity
  • [later] last visited
• [later] Search
• [later] Articles
• [later] Shops
• [later] Favorites
• [MVP] Sandwichbar
  • [MVP] My Shops
    • [later] Filtering
    • [MVP] List own Shops
    • [MVP] New Shop (or edit existing)
      • [MVP] Add pictures / take photos
      • [MVP] Name, Desctiption
      • [later] categories
      • [MVP] link to shop (dropdown with own shops)
      • [MVP] used / new
      • [MVP] Delete(if editing existing) | Save
  • [MVP] My Articles
    *[MVP] similar to Shops
  • [later] notifications
• [MVP] View Shop
  • [MVP] Picture(s) with slide
  • [MVP] Title
  • [later] Map
  • [MVP] Description
  • [MVP] Contact Info
  • [MVP] Opening Times
  • [MVP] List of Articles in that Shop
• [MVP] View Article
  • [MVP] Picture(s) with slide
  • [MVP] Title
  • [MVP] Price [NCTR]
  • [MVP] Description
  • [MVP] Contact Info