Add trusted CA cert setting

[A-Hall]

When using SSL break-and-inspect on AWS traffic, the S3 output plugin breaks with the following error:

[ERROR][logstash.outputs.s3][GN_S3] Error validating bucket write permissions! {:message=>"certificate verify failed", :class=>"Seahorse::Client::NetworkingError"

It would be helpful when using this type of inspection to be able to configure a trusted CA cert for the device doing the DPI.