Adds a wrt-init kind of on the model of git init for starting a stub
directory with wrt.json, archives/, publish/, and templates/.

Also starts to tweak POD a bit.

I went and read:

https://pause.perl.org/pause/authenquery?ACTION=pause_namingmodules

Realized I should probably not name this something with an inscrutable
top-level namespace.  WRT is still inscrutable, I guess, but at least
it's now under App.

- Renames all modules, fixes tests (such as they are)
- Zaps old t/validate/ stuff

These used to live in bpb-kit; moving them in here since they're specific
to the wrt format.

Now uses:

  wrt display
  wrt render-all
  wrt fcgi

It's shorter and the letters are all right there on the keyboard.

Rolls in render.pl stuff from p1k3.  Now gets deployed system-wide,
to /usr/local/bin.