Improve saving of profiles

Profiles are kind of pita. Some things that need to be changed:

• Feeze when AccountProfile::selected is a string that does not exist
• Add redirect delegates (e.g. store an id in the config, but referene an object. AccountProfile::selected)
• properly store them (saving every second on change is a worse idea)
• make thread safe (ConcurrentModificatioException when adding a million accounts. They are saved while modified)
• tests, more tests and tests
• improve all collection storing
• improve observing (just observe ~/.config/minosoft, not every file)
• unbind accounts and servers from config