Spanish Translation and modify the footer

### Please make sure of the following things

- [ ] I have read the [documentation](https://alist.nn.ci).
- [ ] I'm sure there are no duplicate issues or discussions.
- [ ] I'm sure this feature is not implemented.
- [ ] I'm sure it's a reasonable and popular requirement.

### Description of the feature / 需求描述

Hello, my name is Sebastian from Argentina, I'm playing locally with Alist, congratulations people for this impressive piece of software.

I want to translate Alist to spanish, tell me how can I contribute to this. Where is the language files in the repository?

The other thing, I want to modify the footer with institutional reference moving the Powered by Alist inside the right icon. Could you tell me some information about it?

regards

### Suggested solution / 实现思路

_No response_

### Additional context / 附件

_No response_