Backport of https://github.com/sonic-net/sonic-buildimage/pull/12490 into 202211
- Why I did it
Support syslog rate limit configuration feature
- How I did it
Remove unused rsyslog.conf from containers
Modify docker startup script to generate rsyslog.conf from template files
Add metadata/init data for syslog rate limit configuration
- How to verify it
Manual test
New sonic-mgmt regression cases