Add luaposix addon (#261)

* Add luaposix addon

* chore: Update Addon Metadata

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: kayibea

.gitmodules

@@ -235,3 +235,6 @@
 	path = addons/ftl-hyperspace/module
 	url = https://github.com/ranhai613/ftl-hs-lua-lls-addon.git
 	branch = publish
+[submodule "addons/luaposix/module"]
+	path = addons/luaposix/module
+	url = https://github.com/kayibea/lls-posix

addons/luaposix/info.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "https://raw.githubusercontent.com/LuaLS/LLS-Addons/main/schemas/addon_info.schema.json",
+  "name": "POSIX",
+  "description": "Provides definitions for posix Lua API",
+  "hasPlugin": false,
+  "size": 43490
+}