Add 'Start drive' button

[monikakrawczak]

The driver can start the new drive.
It means that the drive is ONGOING.

When the drive is in an ONGOING state, then the menu item changes the title from 'Start new drive' to 'Resume ongoing drive'.

When there is no ONGOING drive, then the 'Start new drive' form contains only 4 fields:

• Date
• Start Location
• Start Mileage
• Car
  All those fields are required.
  At the bottom is the 'Start Drive' button.

When the driver clicks on that button, then:

• the 'Drive start time' timestamp is saved in the local storage and sent to the server when online and drive completed
• 4 listed above field are read-only
• the rest of form's fields are displayed

Change the 'RESET' button in the ONGOING drive to the 'DELETE' which will delete the ONGOING drive.

THE 'SAVE' button also records 'Drive end time' which is sent to the server eventually.

For backend reference see #505

[arturtamborski]

What should happen when user clicks this button again? Should the timestamp update?
Or maybe we should make it one-click-only: click -> rest of form shows up and the button is turned off.

Also, if we will have that button then maybe it will be better to remove the calendar button? Seems kinda pointless to have it if you have the "start" button.