Consider automatic saving of routes

[michaelyfan]

Just so that if the iPad crashes or the app is closed or something, the crewmember doesn't lose all their entered data

[michaelyfan]

Implemented on the web branch, for web deploy. Progress is saved every couple of seconds and saved to cache. On app startup, a route will automatically resume if something is in cache.

Similar code should be copied if automatic saving needs to be deployed on the master (non-web) branch; the web branch is using sembast-web, the non-web version of sembast works similarly