Provides a uniform Rails cache key for all `WayCost`s using their `id`.
Since the `id` field is option, raise an error if the `WayCost` doesn't
have one.

Refs #6097

If a `Route#cost` is missing the method shouldn't fail. Instead, it
should just pass the `WayCost` along without distance & time cost
values. This way we end up with a list of all `WayCost`s for all stop
areas, even the new ones that haven't been run through the TomTom
calculator yet.

Refs #6097

Gives us a way to take `Route#costs` and `WayCost`s created by
`StopAreasToWayCostsConverter` and merge the data together to obtain
complete `WayCost`s including distance and time values.

This will allow us to more easily interact with the Rails cache for
caching `WayCost`s.

Refs #6097

GTFS import (first step)

We use integer values for distance (kilometres) and time (minutes). If
the values aren't very big, like bus stops inside a city for example,
the integer conversion will put distance and time at `0`, which isn't
correct.

To continue to use our chosen measurement units while still displaying
something that makes sense to users, snap any values >0 and <=1 to `1`.

Refs #6404

Route way costs  use tom tom matrix api instead of batch. Refs #6222

New uniqueness validation for ccblocks

Rails serialises `BigDecimal`s as JSON strings to prevent loss of
precision. The `latitude` and `longitude` columns in `StopArea` are
stored as `BigDecimal`s. The trouble is that TomTom's API requires the
latitude & longitude values to be JSON floats, not strings.

Make a new JSON serialiser that converts the `BigDecimal` coordinates to
float to allow the values to be correctly interpreted by the API.

Refs #6222

Using a set ended up not working out. I needed to be able to index into
the list in `#extract_costs_to_way_costs!`, and sets aren't indexable.
This is because they're supposed to be unordered, though modern Ruby
implements `Set` with `Hash` under the hood, which is ordered in Ruby.

I like the idea of having a data structure that automatically eliminates
duplicates, but it wasn't meant to be, because for the extraction to
`WayCost`s, I need an ordered list. Rather than create a new
`OrderedSet` type, I just went the simple route and used an Array,
eliminating the duplicates manually because I know when duplicates are
supposed to occur due to the nature of the data set.

Remove the `#eql?` and `#hash` methods from `TomTom::Matrix::Point`.
Because we're not longer using `Set`, these methods don't need to be
implemented.

Refs #6222