[New arch] Login arch: check URL, check credentials and get user info (basic auth)

[davigonz]

The steps in the login process are:

1. FileDisplayActivity is created.
2. addAccount(...) method from AccountAuthenticator is called, which starts AuthenticatorActivity.
3. User introduces username and password and press login button.
4. AuthenticatorAsyncTask creates two clients (with no accounts) using OwnCloudClientFactory.createOwnCloudClient(...) and perform ExistenceCheckRemoteOperation and GetRemoteUserInfoOperation
5. AuthenticatorActivity waits for AuthenticatorAsyncTask response and creates an Account explicitly using AccountManager if everything worked fine.

TASKS

• Create branch new_arch/2634-basic_auth
• Development tasks
  • Create domain model
    • UserInfo
    • ServerInfo
    • AuthenticationMethod (enum)
  • Create usecases
    • getServerInfo
    • login
    • getUserInfo
  • Create repositories
    • UserRepository
    • ServerRepository
  • Create datasources (remote or local - pending to check)
    • User (Remote)
    • Server (Remote)
  • Save data retrieved for operations (Not needed)
  • Use dependency injection to obtain simple ownCloud clients via new ownCloudClients factory, without considering ownCloud accounts for now. (maybe done, will check)
• Error handling
• Add units tests (instrumented and not instrumented)
• Code review and apply changes requested
• Tests passing
• Merge branch new_arch/2634-basic_auth into new_arch/login

PR

• App: New arch Basic Auth #2809
• Library New arch Basic Auth android-library#302

[michaelstingl]

For Basic Authentication, it would be cool if the URL the user enters could include the username

User entersuser@mycloud.domain.comso username is automatically filled with user and the URL is mycloud.domain.com. In case the username itself includes the "@", users need to use proper URL encoding user%40host@mycloud.domain.com.