New LinkStack release (version 4.0.4)

Bugfix Update

New additions:

• Fixed security check timeout
• Fixed errors with empty custom URL prefix #451
• Fixed email not sending when user registers
• Fixed HTML appearing in social share preview on home page
• Fixed remember me functionality when logging in or registering
• Updated Maintenance Mode to only use the config entry to store maintenance state
• Added option to maintenance page to disable Maintenance Mode directly
• Improved compatibility for updater
• Improved compatibility for theme updater
• Added message when there are no links on the links page
• Added message when there are no links on the dashboard/index page