chore: move the go code into a subfolder

apps/api/internal/cache/connector/redis/_util.lua

@@ -0,0 +1,17 @@
+-- keySetKey returns the redis key of the set containing all keys to the object.
+local function keySetKey (object_id)
+    return object_id .. "-keys"
+end
+
+local function getTime()
+    return tonumber(redis.call('TIME')[1])
+end
+
+-- getCall wrapts redis.call so a nil is returned instead of false.
+local function getCall (...)
+    local result = redis.call(...)
+    if result == false then
+        return nil
+    end
+    return result 
+end