Rm `LocalAppSnippet.setup`

[mishig25]

Follow up to https://github.com/huggingface/huggingface.js/issues/778 and https://github.com/huggingface/huggingface.js/pull/942

After https://github.com/huggingface/huggingface.js/pull/942, I've realized that a better absteraction/generalisation is just to make LocalAppSnippet.content: string | string[] & remove LocalAppSnippet.setup altogether. Instead put what was in LocalAppSnippet.setup as the first item in LocalAppSnippet.content string array