Get working scanning over rgpiod

This includes getting a list of chips, their line numbers, enumerating
the properties of the lines/pins, and providing to the user the list of
valid pins to connect to relays.

It also includes reworking the fake relay system and the configuration
file.

I believe this ends the rampant refactoring and I'll now stabilize out
some features.

templates/relay-create.template.html

@@ -2,9 +2,9 @@
 <h1>Relay Creation</h1>
 <form method="POST" action="/relay/create">
   <input type="text" name="name" placeholder="Pool Pump 1"></input>
-  <select name="chip-and-number">:
+  <select name="pin_id">:
     {% for pin in pins %}
-    <option value="{{ pin.chip }}-{{ pin.number }}">{{ pin.name }}</option>
+    <option value="{{ pin.chip.number }}-{{ pin.chip.name }}-{{ pin.line_number }}">{{ pin.name }}</option>
     {% endfor %}
   </select>
   <button type="submit">Create</button>