Drop support for TLSv1.0

[nabadger]

When configured to listen on SSL TLSv1.0 still supported (we should drop it)

| ssl-enum-ciphers: 
|   TLSv1.0: 
|     ciphers: 
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
|     compressors: 
|       NULL
|     cipher preference: server
|     warnings: 
|       64-bit block cipher 3DES vulnerable to SWEET32 attack
|       Forward Secrecy not supported by any cipher
|   TLSv1.1: 
|     ciphers: 
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
|     compressors: 
|       NULL
|     cipher preference: server
|     warnings: 
|       64-bit block cipher 3DES vulnerable to SWEET32 attack
|       Forward Secrecy not supported by any cipher
|   TLSv1.2: 
|     ciphers: 
|       TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 2048) - A
|       TLS_RSA_WITH_AES_128_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_AES_256_CBC_SHA (rsa 2048) - A
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA (rsa 2048) - C
|     compressors: 
|       NULL
|     cipher preference: server
|     warnings: 
|       64-bit block cipher 3DES vulnerable to SWEET32 attack
|       Forward Secrecy not supported by any cipher
|_  least strength: C

Most likely set min to TLSv1.2:.

Also not sure why we've set a max version tls.VersionTLS12 - should probably avoid specifying this.

Also noted that the error handling around tls certs is poor here (i.e. if the file doesn't exist, so fix that too).