Change link included in tweet for Twitter social verification

[markmhendrickson]

The Explorer link included in a tweet posted during Twitter social verification should be removed and replaced with a shortened version (e.g. bit.ly) to https://blockstack.org/try-blockstack with the following GET parameters appended for tracking:

• utm_campaign=social-verification
• utm_medium=social-media
• utm_source=twitter

[markmhendrickson]

Whoever pushes this change live should also address stacks-archive/blockstack.org#1009 simultaneously or leave a comment on that issue indicating that we're now driving traffic to https://blockstack.org/try-blockstack via Twitter.

[hstove]

Fixed in d5e1ebe