Fix multiple issues with account merging
* The "Aliases" section on MemberInfo was shown even when users have no aliases.
* The mergable hosts raced the SdkConfig loading and would often result in no mergable hosts being allowed - fixed by using a getting instead of setting it in the constructor
* Accounts would be half-merged in a localpart conflict - this is fixed by adding even more mergable checks
Additionally, more verbose logging is added behind a flag for debugging purposes. It's behind a flag because otherwise the browser grinds to a halt.
