Remove deprecated methods and fields

[t3chguy]

Requires matrix-org/matrix-react-sdk#12524

• Removes threepidCreds on EmailIdentityDict - should use threepid_creds
• Removes Room::shouldUpgradeToVersion - should use Room::getRecommendedVersion instead
• Removes user field on UIA calls, uses identifier instead
• Removes address field on Login request interface - should use identifier instead
• Removes IEncryptedFile - should use EncryptedFile on types export instead
• Removes ICrossSigningKey - should use CrossSigningKeyInfo
• Removes IJoinRuleEventContent - should use RoomJoinRulesEventContent
• Removes home_server field on RegisterResponse - should derive from user_id by splitting at the first colon instead

[richvdh]

loving it