Add svelte-css-short-name-preprocess

[Naararouter]

I haven't met the package like this before in Svelte community. Believe, it should be useful for production optimizations.

[TheComputerM]

The length of CSS selectors does not have a major effect on performance, even if they wanted to reduce the length of the css classes, they could use the cssHash in the svelte compiler.

[Naararouter]

This package doesn't affect svelte auto-generated class names, what a purpose for cssHash complier option, as I can see by doc. This is mostly about custom css class names, probably, provided by some css frameworks and etc.