Rename drake/examples/Cars to drake/automotive

[jwnimmer-tri]

Closes #3406.

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This change is

[jwnimmer-tri]

+@rpoyner-tri for feature review, please.

[jwnimmer-tri]

This PR moves the files and updates all path references. A subsequent PR will deal with updating the C++ namespaces and any other loose ends.

[jwnimmer-tri]

+@david-german-tri for platform review, please.
(Doing the reviews concurrently to get this in ASAP; it's very conflict-prone.)

[david-german-tri]

@drake-jenkins-bot linux-clang-experimental-ros please

otherwise

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Review status: 0 of 78 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[david-german-tri]

Reviewed 148 of 148 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved, some commit checks pending.

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Comments from Reviewable

[rpoyner-tri]

Ah, just saw your comment above about further loose ends, such as "drakeCars" and "drake_cars" in various places.

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Reviewed 148 of 148 files at r1.
Review status: all files reviewed at latest revision, all discussions resolved, some commit checks pending.

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Comments from Reviewable

[jwnimmer-tri]

Ah bummer, of course the ROS build is going to fail. I always forget that.

[jwnimmer-tri]

@drake-jenkins-bot linux-clang-experimental-ros please

[rpoyner-tri]

Reviewed 4 of 4 files at r2.
Review status: all files reviewed at latest revision, all discussions resolved, some commit checks pending.

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Comments from Reviewable

[jwnimmer-tri]

Wow. Three hours from starting typing to a merge. Possibly a new personal best.