Switch !pub channels lists to registry

Summary:
Channel configuration for Twitter was hardcoded.

We switched all that to the registy.

Test Plan:
Tested on #wolfplex.

05:55:49 <+Dereckson> !pub We launch Eglide shell hosting service: Freenode Eglide / www.eglide.org / @eglide_project

Works: https://twitter.com/wolfplex/status/819422619158069249

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D824