pki: Make pki_key_ecdsa_nid_to_name() a shared function.

(cherry picked from commit 11cfb2903eb319d32a2432a015c61506f50dc78b)
pki: Move ssh_pki_key_ecdsa_name() to the correct file.

(cherry picked from commit f48a99b97c399174ad35b83a91df922f106ade13)
pki: Correctly update the ECDSA keytype.

(cherry picked from commit 2884bbf5b1bfe915160a1dc03eddbcd000555ec1)
messages: Add missing ntohl on X11 request screen number

BUG: https://red.libssh.org/issues/160

Signed-off-by: Alan Dunn <amdunn@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
pki crypto: expose new ssh_pki_key_ecdsa_name API

Enable retrieving the "ecdsa-sha2-nistpNNN" name of ECDSA keys with a
new 'ssh_pki_key_ecdsa_name' API.  This gives more information than the
'ssh_key_type_to_char' API, which yields "ssh-ecdsa" for ECDSA keys.
The motivation is that this info is useful to have in a server context.

The torture_pki unit test is updated to include the new API, and a few
more passes are added to additionally test 384 and 521-bit keys.

Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
cmake: Update doxygen module.
cmake: Fix doxygen.
pki: Move ssh_pki_key_ecdsa_name() to the correct file.
pki: Add missing semi-colon.
pki: Fix build without ECC support.

Signed-off-by: Andreas Schneider <asn@samba.org>