Add support for Branding

[andtry]

We support branding in our input NeTEx data. We need to create support for this in OTP.

Input data support branding on multiple levels, however our main focus will be support for Branding on Line and Operator.

[barbeau]

FYI, as I mentioned in #3105 (comment), there is a draft spec for an extension to GTFS to handle branding as well - GTFS-ModesAndNetworks (http://bit.ly/gtfs-modes-and-networks).

[github-actions]

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