Have a dissector table for SSL/TLS/DTLS ALPN protocol IDs.

Have a dissector table for SSL/TLS/DTLS ALPN protocol IDs.

Have dissectors register with their protocol ID string in that table,
rather than having a table in epan/dissectors/packet-ssl-utils.c that
has to be updated for new protocols.

Have a table of protocol ID string prefixes, to handle the case of
protocols such as SPDY and HTTP2 drafts, where multiple protocol IDs are
used for different versions.

Change-Id: I363d04895a88e779fbbca7dc8e1f31aa1970a31a
Reviewed-on: https://code.wireshark.org/review/27836
Reviewed-by: Guy Harris <guy@alum.mit.edu>