maui-symbolic: Add credits and rearrange copyright files
maui-symbolic: Add system-lock-screen-symbolic from Breeze
maui-symbolic: Add system-reboot-symbolic from Breeze
maui-symbolic: Add system-suspend-symbolic from Breeze
maui-symbolic: Add system-switch-user-symbolic from Breeze
maui-symbolic: Add system-suspend-hibernate-symbolic from Breeze