Add overloads for std::string_view

[dbaston]

Feature description

GDAL sometimes works with strings as std::string, but the API usage of C style strings necessitates frequent conversion between the two types. Adding overloads or changing signatures to use std::string_view could reduce clutter from frequent conversions between std::string and C strings. If signatures are changed, string comparison functions such as EQUAL would also need to be made available for std::string_view.

Additional context

No response