Use the default target folder for all accounts instead of asking per account

[KofTwentyTwo]

Settings has a "Default target folder", but I still get asked for a destination for every account I add, and I always answer the same thing: the same root drive, one subfolder per org.

Could the default root be the standing choice? With "create an <org> subfolder" on by default, each account would land in <default root>\<org> and the wizard could skip or collapse the destination step whenever a default root is set. An account that really needs its own folder could still opt out and pick one.

Tracked as #120.