Initial Block Explorer Release

The shiniest new feature in this release is the Block Explorer that replaced the basic web interface. It is running live at https://explorer.dcrdata.org/. Here's a quick capture:

Here's the dark theme on a mobile phone:

And a vote information table for each vote transaction:

But the most exciting aspect of this release is that it was a real collaborative effort, with major contributions from several contributors (mostly alphabetical): @gozart1, @McEdward, @raedah, @RogueElement, and @chappjc (myself).

There is a lot more to do -- features to add, issues to fix, tests to write, etc. Even so, this feels like a great start!

Please check back for completed release notes in the next day.