New way to handle "anonymous" accounts

[JohnXLivingston]

Using XMPP anonymous accounts has various inconvenient:

• moderation is difficult
• if users open 2 browser tabs, they will in fact use 2 separate accounts (and there will be nickname conflicts)
• following a user's message history could be difficulte, as the backend account changes everytime.

So, we should implement some kind of "semi-anonymous" users:

• an API on Peertube to request an account
• the account is created on a special Prosody component (with some restriction, as for real XMPP anonymous account: can't speak with the outside world, ...)
• credentials are sent to the browser and stored in session storage to be reused
• accounts are deleted after inactivity

This is also related to #487

Warning: this should not break backward compatibility: instances that have not the livechat up to date should still be able to connect

[vencabot]

Something I would suggest for consideration is that XMPP components can send and receive messages under any account name without needing to create an account on the Prosody database, so maybe that would be even easier. It's what I've been doing for my chat bridge, and it works very well. The process is like this:

• Component sends a Presence status to the group-chat room (Multi-User Chat) of 'Available' -- but instead of supplying its own JID in the 'from' field, it supplies an arbitrary JID of your choosing (something only Components are allowed to do).
• That JID is now considered Available in that MUC and the Component will receive any messages that are labeled 'to' that JID.
• The Component can send chat messages 'from' that JID 'to' the MUC.
• When you want for that 'account' to leave the MUC, you just send a Presence status of Unavailable to the MUC 'from' that JID.
• The Component will no longer receive messages addressed to that JID.

Perhaps it would be easier in some way to create and delete accounts on Prosody, but in case you weren't aware of this mechanism of Components, I wanted to bring it up.

[JohnXLivingston]

Perhaps it would be easier in some way to create and delete accounts on Prosody, but in case you weren't aware of this mechanism of Components, I wanted to bring it up.

But here, there are real users behind the anonymous accounts. So i can't use this.
For the record, i already do something very similar for external accounts.