Add verify mode option to config

[dmosorast]

Description of change

Change verify mode to be an optional config argument, instead of assuming that using an SSH tunnel invalidates the Subject of the SSL cert verification.

verify_mode defaults to "true" and removing it will disable Certificate Name verification on the connection. This is useful if you have a self-signed cert attached to your mongo instance or for some other network topological reason the name verification doesn't apply.

QA steps

• automated tests passing
• manual qa steps passing (list below)
  • None. Relying on automation to run through the code and confirm that this has no effect on existing configs.

Risks

Low, this is an additive optional property. In most cases it should have no effect.

Rollback steps

• revert this branch