Add all members of one channel to another

[ChaseC99]

Create a new page to add all of the members from one channel into another channel.

Call this page /addMembersToChannel or something
It should have 2 drop downs to select the channel where the members are from and the channel where they are being added to. Include a confirmation dialog before Add {# of members} people to {new channel}? [Confirm] [Cancel]

Use .conversations.members to load members from old channel and .conversations.invite to add them to the new one.

Common use cases:

• Adding everyone in #organizers to the #mentors channel
• Adding everyone in #general to a new #photos channel