[3] As a user I want to have default icons for feed providers if no icon is provided, to find feeds in lists fast

When a feed has no icon, a system symbol should be added. For that wildcard-icon one of the 'letter'.square icon from the category "Indizes" should be use. 'letter' must be replace with the first letter of the feeds name (e.g.: NZZ -> n. square; Tagesspiegel -> t. square)

ToDo

Custom:

• change the Default image in asynchronous image constructor call to load a alternative-icon instead of set it to nil

Defaults:

• Report Changes in UML
• Report Changes in Wireframes

Acceptance criteria

Custom:

• Feeds have they own icon or a wildcard-icon

Defaults:

• Naming Convention for Classes, Functions and Variables are met
• Comments are sufficient

Effort:

3