[schema,server] add a security debugging aid (closes #2920304)
- Add a DGB_SEC debugging flag (to be used with set_debug/debugged).
- Add a context manager (tunesecurity) to filter security assertions.
Note: this does not address all read-security mecanisms.
# migrate default format for TriInfo `comment_format` attribute
sync_schema_props_perms('TrInfo')
commit()