Parse the names of children of TabContainers on POT generation

[YeldhamDev]

TabContainer makes use of its children's names to title its tabs, so those should be translated as well. If a child has auto_translate disabled, it will be skipped, as well as all children if the TabContainer itself disabled it.

[KoBeWi]

This can generate false positives if set_tab_title() is used.

[YeldhamDev]

@KoBeWi Then the user can toggle auto_translate off in the respective node (or the container itself), as explained above.

[akien-mga]

Thanks!