[BUG] Series.apply does not retain the Series name

[bdice]

Describe the bug
Calling cudf.Series.apply should retain the Series name to align with pandas.Series.apply behavior. The previous behavior of cudf.Series.applymap (deprecated in favor of cudf.Series.apply) correctly retains the Series name.

Steps/Code to reproduce bug

import pandas as pd
import cudf

ps = pd.Series(range(10), name="awesome_numbers")
result = ps.apply(lambda x: x + 42)
print(result.name)  # awesome_numbers

gs = cudf.from_pandas(ps)
result = gs.apply(lambda x: x + 42)
print(result.name)  # None

gs = cudf.from_pandas(ps)
result = gs.applymap(lambda x: x + 42)  # FutureWarning: Series.applymap is deprecated [...]
print(result.name)  # awesome_numbers

Expected behavior
name should be retained.

[vyasr]

When this issue is fixed I suppose we should also remove https://github.com/rapidsai/cudf/pull/10685/files#r856370814.

[bdice]

When this issue is fixed I suppose we should also remove https://github.com/rapidsai/cudf/pull/10685/files#r856370814.

I have a follow-up PR planned once PRs #10716 and #10685 are merged.

edit: #10738