add insecure skip verify option on clickhouse tls connection

[anthonyminier]

This is an update to add option to ignore TLS certificat verification as asked here: #19

[CLAassistant]

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[bianpengyuan]

Thank you @anthonyminier for the contribution, could you sign the CLA? #21 (comment)

[andreev-io]

Thank you for the contribution!

[anthonyminier]

hello, i just signed the agreeement. Thank you.