Features: Improved QoL for pedestrian mappers part II

[Bonkles]

Description

This omnibus issue will capture all the pedestrian mapping improvements we want to make for H2. For now this will be ideas that the team will review.

(This is a follow-on to #1140 which was completed at the end of 2023).

• Feature request: get gallery of Mapillary images that view an object #1113
• Feature request: make easier to quick label sidewalk tag on roads (left/right/both/none) #1114
• Validations
• New Validation: Crossing Node not part of a Footway crossing #1143
• Add validation to create kerb nodes for pedestrian crossings.  #1460
• Key shortcuts to easily toggle streetview layers #1578

MapRoulette:

• [MapRoulette Integration] Curly braces in instructions aren't replaced #1419
• [MapRoulette Integration] Support MapRoulette templating in challenge instructions #1423
• Combine Tasking Manager task box with MR challenges
  • Counter for remaining tasks
  • "Fly to nearby challenge" on completion #1613
  • Positive signal that there are 'no more' challenges /features in view and that the user is done mapping
  • Constrain loaded challenges to those within the supplied task box (don't show anything outside)
• Preserve MapRoulette task settings in the URL #1422

[eneerhut]

The Strava heatmap mentioned in #1462 could actually be a really interesting addition to assist the pedestrian mapping efforts.