account-registration: add the informational account-required cap

[emersion]

Alternative to #490.

Closes: ircv3/ircv3-ideas#73

cc @slingamn

[emersion]

Here's how my UI looks like. ATM everything is on one screen but I may split the hostname and nickname/password to 2 separate screens in the future.

User fills the first field:

At this point, my client connects to the server, sends CAP LS, then closes the connection. If authentication is required, the UI changes to this and the form refuses to be submitted if the password is empty:

If SASL isn't supported the UI switches to this:

(Advanced settings to set the username/realname/server pass/etc will be added in the future, but are missing for now.)

[emersion]

@slingamn @kylef @jwheare any thoughts on this PR?

[emersion]

Gentle ping

[emersion]

@kylef @jwheare Gentle ping

[jwheare]

My opinion is unchanged since #490 (comment)

[emersion]

Okay. What would it take to merge this?

[emersion]

Gentle ping

[ValwareIRC]

FWIW I don't think this is a great idea to add into account-registration, as it assumes that the registration mechanism is in IRC.

My use case: ircv3/ircv3-ideas#89

I would like to be able to advertise account-required without it meaning that the user should try to register over IRC using account-registration. It just doesn't feel like it fits in this spec.

[emersion]

it assumes that the registration mechanism is in IRC.

There's no such assumption.

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Alright, since there's no positive feedback here, I'll ship this as a vendored cap in soju+goguma.

[progval]

I think it's a fine concept to add to IRCv3, I just don't have anything meaningful to contribute to the discussion