CHANGES.md, NEWS.md: update for 3.6.0-beta1

CHANGES.md, NEWS.md: update for 3.6.0-beta1

CHANGES.md:
 * https://github.com/openssl/openssl/pull/28398
 * https://github.com/openssl/openssl/pull/28411
 * https://github.com/openssl/openssl/pull/28447
 * https://github.com/openssl/openssl/pull/28449

NEWS.md:
 * https://github.com/openssl/openssl/pull/28447

Release: yes
Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28521)