Trusted Setup Client v2

[GhostOfGauss]

Updates the Trusted Setup Client to address two common problems:

• Invalid signatures in registration form: this problem is caused by participants incorrectly copying the relevant information (email, twitter, verifying key, signature) to our registration form. This problem is solved by creating customized links to the registration form that automatically fill in the above fields.
• Error message Registry update is taking longer than expected... for contribute mode was misleading. Participants commonly did not understand that they needed to wait until the ceremony begins to run the client in contribute mode. The error message is now more informative and leads them to a landing page for more information.

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• Linked to an issue with discussion and accepted design OR have an explanation in the PR that describes this work.
• Added one line describing your change in CHANGELOG.md and added the appropriate changelog label to the PR.
• Re-reviewed Files changed in the GitHub PR explorer.
• Checked that changes and commits conform to the standards outlined in CONTRIBUTING.md.

[SupremoUGH]

Should we keep the old messages as well? So people would get their public key + signature separately and then they have the link to the google form. Also this way we don't have to update the docs.

[GhostOfGauss]

I prefer to keep the output of the client as simple as possible, so I think v2 should only display the link.

I can include a section in the docs that addresses v1 clients, but I plan to update the docs to assume v2.

[bhgomes]

For the screenshot can use another one with the standard window size to see the wrapping (even if you wanted to use a wide one which I don't recommend, the one you posted has one character on the next line which is easy to miss).