LB-860: On Manage Collaborators -> add new collaborators, it is showed only first 20 collaborators.
* limit-filter added
Merge branch 'liveblog-15' into lb-860-limits-for-collab-list

Conflicts:
	plugins/livedesk/livedesk/impl/blog_collaborator.py
Merge pull request #271 from msat-cont/lb-860-limits-for-collab-list

LB-860: limits for collab list