Implement login redirect for dashboard page

[chriszhangusc]

1. Redirect to the home page when trying to access dashboard page without authentication.
2. Redirect to the home page when login is canceled by the user or failed for whatever reasons.

[rwieruch]

That sounds perfect @minipekka Thanks for improving/fixing it! I didn't test it, but I believe you did, so I will just merge it 👍

[chriszhangusc]

@rwieruch I double checked just in case, and I found a bug..... Sorry I failed you haha. I will make a patch for it.

[chriszhangusc]

#78 I will create some tests for the newly added code. Also, I think it might be a good idea to also update the sister project to keep things in sync.