Add a util router to retrieve all CPU names

[da-ekchajzer]

Problem

As mention in #155 we should add a new /utils router for retrieving all available CPU names.

Solution

@utils_router.get('/cpu_name', description=cpu_name)
async def utils_get_all_cpu_name():
    df = _cpu_index[_cpu_index["name"].notna()]
    return [*df["name"].unique()]