Make user synch optional

Have added some remarks.

Just fixed a coding standard issue and renamed the variable from userSync to user_sync since this is the name that's been used for the config entity property according to the annotation of the entity. I then realized that the config schema needed to be updated as well.

The getter for boolean config values should do the casting for some reason. I have seen issues in the past where reading config yamls didn't do that properly sometimes and we then had an integer value instead.

Otherwise, this looks good to go.

Thx a lot.

Automatically closed - issue fixed for 2 weeks with no activity.