Improve ephemeral key handling (companion to r1526168):
- allow to configure custom DHE or ECDHE parameters via the SSLCertificateFile directive, and adapt its documentation accordingly (addresses PR 49559)
- add standardized DH parameters from RFCs 2409 and 3526, use them based on the length of the certificate's RSA/DSA key, and add a FAQ entry for clients which limit DH support to 1024 bits (such as Java 7 and earlier)
- move ssl_dh_GetParamFromFile() from ssl_engine_dh.c to ssl_util_ssl.c, and add ssl_ec_GetParamFromFile()
- drop ssl_engine_dh.c from mod_ssl
For the standardized DH parameters, OpenSSL version 0.9.8a or later is required, which was therefore made a new minimum requirement in r1527294.
PR 55616 (add missing APLOGNO), part 2 Submitted by: kbrand Reviewed/backported by: jim