Add a loading bar for Unity WASM

[eordano]

Similar to the one on the renderer, let's provide some feedback for the user while they are loading the unity.data.wasm and unity.wasm files

With a loading bar like

Also for Desktop

[eordano]

This should be enough information to show that progress:

explorer-website/src/state/reducers.ts

Lines 147 to 153 in 8bf1e9b

	if (action.type === SET_DOWNLOAD_PROGRESS) {
	state = { ...state, progress: action.payload.progress, currentState: DownloadCurrentState.DOWNLOADING }
	} else if (action.type === SET_DOWNLOAD_READY) {
	state = { ...state, progress: action.payload.progress, currentState: DownloadCurrentState.READY }
	} else if (action.type === SET_DOWNLOAD_NEW_VERSION) {
	state = { ...state, progress: action.payload.progress, currentState: DownloadCurrentState.NEW_VERSION }
	}