File upload validation

[olafveerman]

In Phase 2, we will implement more advanced file validations that should trigger clear warnings and errors towards the users. This is a placeholder ticket to start gathering such validations.

File	Validation	Type
Origins	Check if all features (villages) have valid population estimates (Number). We can't analyze those that don't have	Warning
Origins	Check if there is at least one feature with an estimate	Error
Destinations
Road Network
Admin boundaries	Check if the features have the 'name' attribute	error
OSRM Profile

cc @danielfdsilva

[olafveerman]

Starting a list with problems we encountered with the profile lua:

speeds = Sequence {
  highway = {
     "4"           = 30,
  }
}

Results in:

Should be ["4"]