Feature Request: pd.MultiIndex.from_frame(). Complement to pd.MultiIndex.to_frame().
The MultiIndex.to_frame function is great for working with multi-indexes as a meta-dataframe. I find myself using this paradigm very often.

    df = create_multiindex_df()
    meta = df.columns.to_frame(index=False)
    meta = filter_multiindex()
    df.reindex(columns=convert_df_to_multiindex(df))

Having the `convert_df_to_multiindex` as a pd.MultiIndex method would be extremely complimentary to `pd.MultiIndex.to_frame`.

A simplified one-line implementation provided below, not including accounting for some corner case behaviors and discerning between series/frames vs Index/Multiindex.

    pd.MultiIndex.from_tuples(list(df.values), names=df.columns)

