Implement "account delegation"

[ewinslow]

In some cases I could see it being useful for users to allow other users to act on their behalf. E.g. create an account for a team and then allow members of the team to act on behalf of the team.

Here's how I imagine it working:

• Create a new account "The Team"
• Go to /settings/account and add "The Person" as an administrator of the account.
• Log out and log in as "The Person".
• Select from a topbar dropdown to act as "The Team" (no need to type "The Team"s password)
• Everything you do will be attributed to "The Team"