common: add openssl engine support

common: add openssl engine support

this patch enables the use of openssl engine for
specific openssl algorithm(like DIGESTS/CIPHERS/...)

we can pass configuration to ceph by opt "openssl_engine_opts"
like "engine_id=engine1,dynamic_path=/some/path/engine1.so,
default_algorithms=DIGESTS:engine_id=engine2,dynamic_path=
/some/path/engine2.so,default_algorithms=CIPHERS,
other_ctrl=other_value"

Signed-off-by: Hang Li <lihang48@huawei.com>
Signed-off-by: luo rixin <luorixin@huawei.com>