gh-100062: Remove error code tables from _ssl and err_names_to_codes (GH-100063)

Prior to https://github.com/python/cpython/pull/25300, the
make_ssl_data.py script used various tables, exposed in _ssl, to update
the error list.

After that PR, this is no longer used. Moreover, the err_names_to_codes
map isn't used at all. Clean those up. This gets them out of the way if,
in the future, OpenSSL provides an API to do what the code here is doing
directly. (https://github.com/openssl/openssl/issues/19848)