Is it permissible to sell templates of computer designs with the possibility of them being used in content that violates Islamic Sharia, and would the money earned from that be unlawful?

What can be used for both lawful and unlawful purposes is, in principle, permissible, unless it is highly probable that its use will be unlawful. Thus, anything that is used in an unlawful manner, or is highly likely to be so used, is forbidden to manufacture, import, sell, or promote.