OpenVPN RW page: Show CA and server certificate start, finish, and expiration warning

[Tbaile]

To help administrators monitor certificate expiration, the OpenVPN Roadwarrior (RW) page should display information regarding the start and finish dates of both the Certificate Authority (CA) and server certificate.

Proposed solution
The RW webpage should:

• Show the start and expiration (finish) dates of both CA and server certificate.
• Display a warning on the page when the certificate is within one month of expiration.
• Show the remaining number of days until expiration only when a month , allowing administrators to plan renewals.
  The information should be visible directly within the Roadwarrior VPN configuration area so it is readily available.