Expose stream parameter in public strings convert APIs

[davidwendt]

Description

Add stream parameter to public APIs:

• cudf::strings::to_booleans()
• cudf::strings::from_booleans()
• cudf::strings::to_timestamps()
• cudf::strings::from_timestamps()
• cudf::strings::is_timestamp()
• cudf::strings::to_durations()
• cudf::strings::from_durations()
• cudf::strings::to_fixed_point()
• cudf::strings::from_fixed_point()
• cudf::strings::to_floats()
• cudf::strings::from_floats()
• cudf::strings::is_float()
• cudf::strings::to_integers()
• cudf::strings::from_integers()
• cudf::strings::is_integer()
• cudf::strings::hex_to_integers()
• cudf::strings::integers_to_hex()
• cudf::strings::is_hex()
• cudf::strings::ipv4_to_integers()
• cudf::strings::integers_to_ipv4()
• cudf::strings::is_ipv4()
• cudf::strings::url_encode()
• cudf::strings::url_decode()
• cudf::strings::format_list_column()

Also cleaned up some of the doxygen comments and removed some default parameters.

Reference #13744

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[ttnghia]

Probably there will be a lot more changes needed to change strings, integers, etc. into input name in the internal APIs.

[davidwendt]

Probably there will be a lot more changes needed to change strings, integers, etc. into input name in the internal APIs.

The intention was to change strings to input because strings is part of the namespace name and sometimes produces confusing compile errors. We don't have the same issue with other types like booleans and integers so I'd like to leave those unchanged.

[mythrocks]

LGTM! A couple of minor questions.

[davidwendt]

/merge