MINOR: ssl: Add curve id to curve name table and mapping functions

MINOR: ssl: Add curve id to curve name table and mapping functions

The SSL libraries like OpenSSL for instance do not seem to actually
provide a public mapping between IANA defined curve IDs and curve names,
or even a mapping between curve IDs and internal NIDs.
This new table regroups all those information in a single table so that
we can convert curve names (be it SECG or NIST format) to curve IDs or
NIDs.
The previously existing 'curves2nid' function now uses the new table,
and a new 'curveid2str' one is added.