LB-849 : Add the option to hide posts on collaborators, SMS, chained blogs and user comments

Add the option to hide posts on collaborators, SMS, chained blogs and
user comments

The chained blogs are now read by the backend and on chained blog source
all posts are read from local instance through the
getUnpublishedBySource service
LB-849

Add the option to hide posts on collaborators, SMS, chained blogs and user comments
LB-849  Add the option to hide posts on collaborators, SMS, chained blogs and user comments

Added support to get the list of chained blog sources by blogId
LB-1117 : Auto-publish not works for chained blogs

Added 'User-Agent' : 'Magic Browser' header to the request