Update Diffie-Hellman parameters to IANA standards

This replaces the old SKIP primes with the most current Diffie-Hellman
MODP groups defined by RFC 7296 and RFC 3526.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from GitHub https://github.com/openssl/openssl/pull/775)

apps/dh1024.pem

 -----BEGIN DH PARAMETERS-----
-MIGHAoGBAPSI/VhOSdvNILSd5JEHNmszbDgNRR0PfIizHHxbLY7288kjwEPwpVsY
-jY67VYy4XTjTNP18F1dDox0YbN4zISy1Kv884bEpQBgRjXyEpwpy1obEAxnIByl6
-ypUM2Zafq9AKUJsCRtMIPWakXUGfnHy9iUsiGSa6q6Jew1XpL3jHAgEC
+MIGHAoGBAP//////////yQ/aoiFowjTExmKLgNwc0SkCTgiKZ8x0Agu+pjsTmyJR
+Sgh5jjQE3e+VGbPNOkMbMCsKbfJfFDdP4TVtbVHCReSFtXZiXn7G9ExC6aY37WsL
+/1y29Aa37e44a/taiZ+lrp8kEXxLH+ZJKGZR7OZTgf//////////AgEC
 -----END DH PARAMETERS-----
 
-These are the 1024 bit DH parameters from "Assigned Number for SKIP Protocols"
-(http://www.skip-vpn.org/spec/numbers.html).
-See there for how they were generated.
-Note that g is not a generator, but this is not a problem since p is a safe prime.
+These are the 1024-bit DH parameters from "Internet Key Exchange 
+Protocol Version 2 (IKEv2)": https://tools.ietf.org/html/rfc5996
+
+See https://tools.ietf.org/html/rfc2412 for how they were generated.

apps/dh2048.pem

 -----BEGIN DH PARAMETERS-----
-MIIBCAKCAQEA9kJXtwh/CBdyorrWqULzBej5UxE5T7bxbrlLOCDaAadWoxTpj0BV
-89AHxstDqZSt90xkhkn4DIO9ZekX1KHTUPj1WV/cdlJPPT2N286Z4VeSWc39uK50
-T8X8dryDxUcwYc58yWb/Ffm7/ZFexwGq01uejaClcjrUGvC/RgBYK+X0iP1YTknb
-zSC0neSRBzZrM2w4DUUdD3yIsxx8Wy2O9vPJI8BD8KVbGI2Ou1WMuF040zT9fBdX
-Q6MdGGzeMyEstSr/POGxKUAYEY18hKcKctaGxAMZyAcpesqVDNmWn6vQClCbAkbT
-CD1mpF1Bn5x8vYlLIhkmuquiXsNV6TILOwIBAg==
+MIIBCAKCAQEA///////////JD9qiIWjCNMTGYouA3BzRKQJOCIpnzHQCC76mOxOb
+IlFKCHmONATd75UZs806QxswKwpt8l8UN0/hNW1tUcJF5IW1dmJefsb0TELppjft
+awv/XLb0Brft7jhr+1qJn6WunyQRfEsf5kkoZlHs5Fs9wgB8uKFjvwWY2kg2HFXT
+mmkWP6j9JM9fg2VdI9yjrZYcYvNWIIVSu57VKQdwlpZtZww1Tkq8mATxdGwIyhgh
+fDKQXkYuNs474553LBgOhgObJ4Oi7Aeij7XFXfBvTFLJ3ivL9pVYFxg5lUl86pVq
+5RXSJhiY+gUQFXKOWoqsqmj//////////wIBAg==
 -----END DH PARAMETERS-----
 
-These are the 2048 bit DH parameters from "Assigned Number for SKIP Protocols"
-(http://www.skip-vpn.org/spec/numbers.html).
-See there for how they were generated.
+These are the 2048-bit DH parameters from "More Modular Exponential 
+(MODP) Diffie-Hellman groups for Internet Key Exchange (IKE)": 
+https://tools.ietf.org/html/rfc3526
+
+See https://tools.ietf.org/html/rfc2412 for how they were generated.

apps/dh4096.pem

 -----BEGIN DH PARAMETERS-----
-MIICCAKCAgEA+hRyUsFN4VpJ1O8JLcCo/VWr19k3BCgJ4uk+d+KhehjdRqNDNyOQ
-l/MOyQNQfWXPeGKmOmIig6Ev/nm6Nf9Z2B1h3R4hExf+zTiHnvVPeRBhjdQi81rt
-Xeoh6TNrSBIKIHfUJWBh3va0TxxjQIs6IZOLeVNRLMqzeylWqMf49HsIXqbcokUS
-Vt1BkvLdW48j8PPv5DsKRN3tloTxqDJGo9tKvj1Fuk74A+Xda1kNhB7KFlqMyN98
-VETEJ6c7KpfOo30mnK30wqw3S8OtaIR/maYX72tGOno2ehFDkq3pnPtEbD2CScxc
-alJC+EL7RPk5c/tgeTvCngvc1KZn92Y//EI7G9tPZtylj2b56sHtMftIoYJ9+ODM
-sccD5Piz/rejE3Ome8EOOceUSCYAhXn8b3qvxVI1ddd1pED6FHRhFvLrZxFvBEM9
-ERRMp5QqOaHJkM+Dxv8Cj6MqrCbfC4u+ZErxodzuusgDgvZiLF22uxMZbobFWyte
-OvOzKGtwcTqO/1wV5gKkzu1ZVswVUQd5Gg8lJicwqRWyyNRczDDoG9jVDxmogKTH
-AaqLulO7R8Ifa1SwF2DteSGVtgWEN8gDpN3RBmmPTDngyF2DHb5qmpnznwtFKdTL
-KWbuHn491xNO25CQWMtem80uKw+pTnisBRF/454n1Jnhub144YRBoN8CAQI=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=
 -----END DH PARAMETERS-----
 
-These are the 4096 bit DH parameters from "Assigned Number for SKIP Protocols"
-(http://www.skip-vpn.org/spec/numbers.html).
-See there for how they were generated.
-Note that g is not a generator, but this is not a problem since p is a safe prime.
+These are the 4096-bit DH parameters from "More Modular Exponential 
+(MODP) Diffie-Hellman groups for Internet Key Exchange (IKE)": 
+https://tools.ietf.org/html/rfc3526
+
+See https://tools.ietf.org/html/rfc2412 for how they were generated.