Docs for installing `tracy` on non-Windows platforms are lacking

## How can Bevy's documentation be improved?

I just got this set up on PopOs (Linux, Ubuntu). I documented the steps I took and my confusion in [this thread](https://discord.com/channels/691052431525675048/1095746008551542925/1095746008551542925).

Key steps:

1. Clone the [`tracy` repo](https://github.com/wolfpld/tracy), and checkout the correct tag.
2. Install `pkg-config, glfw, freetype, capstone, dbus`. Names may vary.
3. `cd` into the `capture/build/unix` folder and run `make release LEGACY=1` (legacy flag is for wayland support).
4. Do the same for `profiler/build/unix`.
5. Open the profiler folder in your CLI, then call `./Tracy-release`.
6. Follow existing instructions to actually use the GUI with Bevy.