Add TLS and Client certificate support

[ahelmbr]

Additional to the basic CONNECT - the user should be able to run the command with tls usage
and Client certificates

Add
--cafile : path to a file containing trusted CA certificates to enable encrypted certificate based communication.
--capath : path to a directory containing trusted CA certificates to enable encrypted communication.
--cert : client certificate for authentication, if required by server.
--key : client private key for authentication, if required by server.
--ciphers : openssl compatible list of TLS ciphers to support.
--tls-version : TLS protocol version, can be one of tlsv1.2 tlsv1.1 or tlsv1.3

Defaults to tlsv1.2 if available.

Add new options to README.adoc

[gitseti]

• Currently only self-signed certificates are supported for --cert option
• Only openssl RSA keys are supported for --key option

[gitseti]

• Currently only self-signed certificates are supported for --cert option

This issue was resolved by itself because the broker checks the certificate chain.