Generate index page for all reports

[pixeldesu]

Having a index page at hand (that would also get updated with every change) would be quite handy. Requires a second JSON file storing all recent reports.

Schema:

{
  "reports": [
    "12435235...",
    "11324091...",
    "..."
  ]
}

We can just generate the dates back out of the UNIX timestamps or just leave it at Report #231190491.

This requires another template and with that a refactor of moving all required templates into a templates/ subdirectory.