Consider other labels to be exempt from autoclosure

Label	Comment	Approved for exemption
~backstage	Backstage improvements are like ~"technical debt"	✅
security	Security fixes probably shouldn't be autoclosed	✅
customer	Support team applies this label for paying customers	✅
test	Applied to test improvements	✅
development guidelines	Relates to dev guide docs	❌
schema redesign	Database schema redesign	❌
direction	Roadmap features	❌

/cc @rymai @meks