New Features for ADN Module

* Optional Announcement fallback to Podcast Image
* Show Image in Announcement Preview
Added Support for various scientific networks

* ResearchGate
* ORCiD
* Scopus

The icons of the services must be added!
Added Icons
Merge pull request #534 from podlove/scientific-networks

Scientific networks
merge
update readme
New Icons for ORCiD and Scopus
support "duplicate post" plugin

- regenerate guid
- copy contributions

issue #538
Merge pull request #536 from podlove/orcid-scopus-icons

New Icons for ORCiD and Scopus
merge