`Shift` route highlight for other tools

[originalfoo]

On Priority Roads tool, holding Shift highlights the route that will be affected - it's great feedback for user as it simultaneously indicates that a route will be changed and also shows what that route is.

Can we get the same feature added to:

• Speed Limits tool
• Parking Restrictions tool
  • Maybe fade overlay (well, make more transparent) for any roads along route that don't have parking; still show the road as part of route, but faded overlay gives cue nothing will happen on that segment
• Vehicle Restrictions tool

This will ensure great consistency across all tools in relation to Shift key visual feedback.

cc: @kianzarrin

[originalfoo]

Also, it might merit making a start on something akin to #630

[originalfoo]

Tagging relevant PRs where this was added: #708, #709 and #721