Etherpad has a limitation of 50 characters for it's pad ids. Although
our SHA1 hash function generates 40 characters length values, after
prefixing (Meteor's instance id) and suffixing (closed captions support)
the pad id we can reach an invalid size.

Isolate most Pad related functions and secure shared notes and closed
captions creation to only when there is a reachable Etherpad server
configured.