Traffic sign requests

[d99m]

Traffic signs below have been requested in mapillary/traffico.

NOTE: Adding a new sign doesn't mean we'll start detecting it, since we have to enable that functionality in the backend

• speed-/traffic camera (EU, US, UK), see https://github.com/mapillary/traffico/issues/45
• Generic bike route (US), see https://github.com/mapillary/traffico/issues/40
• Living zone on/off (US, EU), see https://github.com/mapillary/traffico/issues/36