Localization (#15)

## Changes (escoria-core)
> Pending to do a PR to the core.
- Added `es` langcode with the corresponding flag image.
- Translated literals for `es`

## Changes (gymkhana)
-  Added `turno_cocina` localization csv.
- Proof of concept for tooltips & dialogs.

## Notes
- For tooltips just use the literals. Godot will automatically search for a translation key first.
- For ESC just use `translation_key:"Default text"`

## How to test
- In the option menu ES should be selectable.
- The `frontal` item in the inventory should have the tooltips and the `say` command translated in `en`,`fr` and `es`.

Reviewed-on: gymkhana/gymkhana#15
Co-authored-by: oier <oierbravo@gmail.com>
Co-committed-by: oier <oierbravo@gmail.com>

gymkhana/rooms/turno_cocina/cocina_delante/esc/cocina_delante.esc

@@ -25,7 +25,7 @@
     set_gui_visible false
     walk_block player puerta_cocina_start
     set_angle player 180
-    say current_player "Alo Uli!"
+    say current_player hello_start_game:"Alo Uli!"
     set_gui_visible true
     accept_input ALL