Add luacheck, update translations, replace ABMs, bug fixes (#1)

* luacheck, mt 5 translation, german translation, maintenance

* fix luacheck warnings

* Fix digital clock nodebox and texture

* Fix luacheck usage

* Add comment why fonts are not split into several lines

ontime_clocks/locale/ontime_clocks.de.tr

@@ -0,0 +1,7 @@
+# textdomain: ontime_clocks
+Green digital clock=Grüne Digitaluhr
+Red digital clock=Rote Digitaluhr
+White clock=Weiße Uhr
+Frameless clock=Rahmenlose Uhr
+Frameless gold clock=Rahmenlose goldene Uhr
+Frameless white clock=Rahmenlose weiße Uhr