[FEATURE REQUEST] Optional cost function

[LdDl]

Is your feature request related to a problem? Please describe.
There is no way to create cost field other then distance metric (kilometers)

Describe the solution you'd like and provide pseudocode examples if you can
Provide flag to CLI called cost_type (default value could be 'kilometers').
Possible values: 'kilometers', 'minutes', 'seconds', 'meters'
'kilometers' and 'meters' are easy to do (first metric has been done already), but 'minutes' and 'seconds' should depend on speed + distance parameter

Additional context
We need to document this functionality and its restrictions properly
Would be cool to have CSV field cost_type as description for weight column also