feature: Remove special characters form file names on creation / upload

[preetamslot]

I have Spanish client, so page titles have allot of special characters, I would love that file names would be stripped from this.

ra-qué-es-el-diseño.md => ra-que-es-el-diseno.md

Images are also a problem, this becouse the optimizer crashes
so ra-qué-es-el-diseño.jpg causes a build error