Backport #34142 by @lunny
Fix the bug when deleting orphaned issues attachments. The attachments
maybe stored on other storages service rather than disk.
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Fix#29074 (allow to disable all builtin apps) and don't make the doctor
command remove the builtin apps.
By the way, rename refobject and joincond to camel case.
