An initial stab at documentation generation (#360)

This adds documentation comments to many of CC's Lua APIs, and
a couple of the Java ones, through the use of stubs. We then
export these to HTML using illuaminate [1] and upload them to our
documentation site [2].

Uploads currently occur on pushes to master and any release/tag. The
site is entirely static - there is no way to switch between versions,
etc... but hopefully we can improve this in the future.

[1]: github.com/SquidDev/illuaminate/
[2]: https://tweaked.cc/

doc/stub/os.lua

@@ -0,0 +1,17 @@
+function queueEvent(event, ...) end
+function startTimer(delay) end
+function setAlarm(time) end
+function shutdown() end
+function reboot() end
+function getComputerID() end
+computerID = getComputerID
+function setComputerLabel(label) end
+function getComputerLabel() end
+computerLabel = getComputerLabel
+function clock() end
+function time(timezone) end
+function day(timezone) end
+function cancelTimer(id) end
+function cancelAlarm(id) end
+function epoch(timezone) end
+function date(format, time) end