Support multiple blogs

[vickychijwani]

Pro users would like the option to sign in to multiple blogs and switch between them seamlessly.

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Task list:

• Rework storage architecture alongside other breaking changes for Ghost 1.0 (Ghost 1.0 vickychijwani/quill#162)
• Build UI for adding / removing blogs and switching among them
• Remove android:launchMode="singleTop" attribute from LoginActivity in the manifest
• Add lots of logging in AccountManager to help debug any issues that come up
• Handle scenario where the password has changed
• Test cases:
  • Trying to add a new account with a blog that was already added earlier (only allow a single account per blog)
  • Preserve the data Realm in the case where, e.g., credentials expire
  • Delete the data Realm when a blog is removed (i.e., explicitly logged out)

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Migrated from vickychijwani/quill#148

[jlelse]

Any updates on this?