Examples cleanup

[rparrett]

I feel like there is a lot left to do here, but this branch is getting large and I'm running out of time.

I tested all examples and their keyboard functionality. texture_vec texture_container were already broken and the problem wasn't obvious so I didn't touch them.

My main goal was to center a bunch of tilemaps and improve consistency of tilemap spawning code between examples, but I stumbled on a few other little cleanups.

I'd recommend reviewing individual commits.

[bzm3r]

This is a welcome standardization fix. Thanks for taking the time to do it.

My main question is around the removal of map_transform in the multiplication with the tile center's transform. Can you comment?

[rparrett]

Note: there is currently (perhaps a) system ordering issue in hexagon_generation. On some runs, switching map types results in empty tiles in the maps. On other runs, it works fine. This behavior was also present prior to this PR, but I'm looking into it.

edit: documented that here: #362

[StarArawn]

@rparrett Is this ready for review again? Also the conflicts need to be fixed.

[rparrett]

Rebased. Looks like there's consensus on removing tile labels from bevy's hierarchy. I should be able to get that done later today.