languages sub directory

langauges no longer clutter the plugin directory

`langauge/init.lua` will load all languages as the plugins loader does.
(literally copy pasted, but fenced to avoid a "require overflow")

data/plugins/language/init.lua

@@ -0,0 +1,16 @@
+local core = require "core"
+
+local no_errors = true
+local files = system.list_dir(EXEDIR .. "/data/plugins/language")
+for _, filename in ipairs(files) do
+  local langname =  filename:gsub(".lua$", "")
+  if langname ~= "init" then
+    local ok = core.try(require, "plugins.language." .. langname)
+    if ok then
+      core.log_quiet("Loaded language %q", langname)
+    else
+      no_errors = false
+    end
+  end
+end
+return no_errors