Support for TPM (with Openssl/Tpm2-openssl)

Hello,

I was interested in using the TPM with the openssl tls plugin. 

To have it work, I need to build with OPENSSL_NO_DEPRECATED_3_0  defined. 

When I build with OPENSSL_NO_DEPRECATED_3_0:

• handle method in qtlskey_openssl  returns "NULL"

• toPem method in qtlskey_openssl  also returns empty string 

Here are the updated files: 

• qopenssl_p  (src/plugins/tls/openssl/qopenssl_p.h)
• qtlsbackend_openssl (src/plugins/tls/openssl/qtlsbackend_openssl.cpp)
• qtlskey_openssl (src/plugins/tls/openssl/qtlskey_openssl.cpp)

You will also find a patch detailing the changes i did to have it work: tpm-support.patch

Thanks