Add a pre commit hook to lint code

This uses pre-commit [1] to check patches are well formed and run
several linters on them. We currently do some boring things (check files
are syntactically valid) as well as some project-specific ones:
 - Run illuaminate on the Lua files
 - Run checkstyle on Java

[1]: https://pre-commit.com/

src/main/resources/data/computercraft/lua/rom/apis/colours.lua

@@ -5,7 +5,7 @@
 
 local colours = _ENV
 for k, v in pairs(colors) do
-	colours[k] = v
+    colours[k] = v
 end
 
 --- Grey. Written as `7` in paint files and @{term.blit}, has a default

src/main/resources/data/computercraft/lua/rom/autorun/.ignoreme

@@ -1,4 +1,4 @@
 --[[
 Alright then, don't ignore me. This file is to ensure the existence of the "autorun" folder, files placed in this folder
 using resource packs will always run when computers startup.
-]]
+]]