RFE: ability to autosave configuration

[sebastien-rosset]

Is your feature request related to a problem? Please describe.
When using other routing software such as qtvlm, there is no requirement to save the routing configuration every time the routing is changed. The user must currently ensure the routing configuration is saved after making changes. If the user forgets to save the routing configuration and OpenCPN crashes or the OS crashes, the routing configuration is lost.

Describe the solution you'd like
Provide capability to automatically save the routing configuration, either on every change or every X minutes.

Describe alternatives you've considered
The user must manually save the configuration.

Additional context
Add any other context or screenshots about the feature request here.