Add troubleshooting article

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  Can I provide encrypted user passwords via mass deployment
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  Can I use self-signed certificates for secure provisioning
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  Can I use two snom phones for VPN without additional equipment
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  Does this phone series support encrypted calls via TLS and SRTP
• Page:
  How can I set up Snom phones for TCP support
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  Security FAQ
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  Vpn Issue
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  Where can I find the supported CAs