Add skipping functionality

[bnb]

In the CommComm, @mhdawson noted that the TSC skips their meetings when there's a light agenda. It may be worth adding some kind of functionality that either automatically skips (if less than a user-supplied number of agenda items, create an issue but apply a skip label or something like that) or allows members to manually skip.

ref: nodejs/community-committee#649 (comment)