Support multiple Tilesets

[joshuajbouw]

What problem does this solve or what need does it fill?
It is ideal not to just use a single tileset but to actually define which tileset to use per tile. They MUST be identified by a integer and not a Handle to reduce cost of bytes per tile.

Describe the solution would you like?
This is mostly a Tile implementation level feature. There should be logic that has a HashMap at the Tile Map level of all handles and then the Tiles simply reference the index location.

Describe the alternative(s) you've considered?
n/a

Additional context
https://www.reddit.com/r/rust/comments/jntjp8/with_the_launch_of_bevy_game_engine_03_im/gb3u25f?utm_source=share&utm_medium=web2x&context=3

[joshuajbouw]

This is mostly closed with this update: 5956f45

Now you can just use multiple tile maps if you want to use multiple sprite sheets.