Ability to logout from frontend

[campb303]

Can't do it. Should be able to.

[campb303]

Logging out can be achieved by setting the isLoggedIn variable to false from the AuthProvider component.

[campb303]

Depends on #49

[wrigh393]

The PR for #49 has just been opened, but here is how logging out was implemented assuming that it will be merged in a similar way to how it functions now.

Because we have context providers toggling the login state required importing the useLoginSetter hook to set the value of that determines if the user is logged in to false

Because the access token is stored in a cookie, if a user logged out they would still be able to navigate to the AppView without having to log in again. In order to fix this problem the cookie that contains the access token that allows users to access the AppView needs to be deleted when a user logs out. This was easy to implement as react-cookie, the library that we are using to manage cookies provides functionality that can delete cookies.

Both of these were implemented in a function that is passed to the ItemAppBarActions component created in #49. Here is how that implementation works.

handleLogout function

	const setLogin = useLoginSetter();
	const setToken = useTokenSetter();
	const [cookies, removeCookie] = useCookies(["csrf_refresh_token"]);

	const handleLogout = () => {
		setLogin(false);
		removeCookie(["csrf_refresh_token"])
	}

ItemAppBarActions implementation

<ItemAppBarActions
tooltipTitle={"Logout"}
onClick={() => handleLogout()}
icon={<LogoutIcon />}
/>

[wrigh393]

Now that actions are passable to the ItemTableAppbar logout functionality is available. It uses the same functions as before, which I will list again below.

handleLogout function

	const setLogin = useLoginSetter();
	const [cookies, removeCookie] = useCookies(["csrf_refresh_token"]);

	const handleLogout = () => {
		setLogin(false);
		removeCookie(["csrf_refresh_token"])
	}

This function does two things:

1. It set the loggedIn state variable to false, thus sending the user back to the login screen.
2. It removes the cookie that stores the user's refresh token. Without removing this cookie even if the user wasn't logged in they would still be able to navigate to the ItemTable.

These work together to make it so a user has to log back in after they click the logout button.

[campb303]

Closed in #226