Breaking: Remove + added channel

• BREAKING: Removed channel changedByUser as it was constantly flooded with updates
• Added channel unlockedByUser that aims to only be updated when an actual unlock operation has taken place. Manual if door knob is used, otherwise <Firstname> <Lastname> of registered user. Note: Please test and report back, it isn't clear to me how to handle these events as an unlock operation usually triggers multiple events. Logs are necessary.
• Fixed concurrency issue for multiple locks registering at the same time - leading sometimes to an event listener being lost upon binding reload
• Added handling of invalid email/phone/password combination with better error message
• Improved thing/channel category