clean up the "login" and "create account" pages and make them look nice

[alexrudnick]

They're intentionally crummy looking right now -- make them look good!

• take out the alerts() and the misspellings, especially!
• oh, and they need localization too.

[taylskid]

We also might consider separating the manually-created login accounts from the more typical Persona login to make it less confusing for the end-user.

[alexrudnick]

OK, it's not terrible! If @albsama has feedback from users, we can change it later, obvs.