Add HLD for Orchagent error handling improvements

[prabhataravind]

This HLD change attempts to address the following:

• Handle all ASIC/SAI programming errors gracefully without causing orchagent to crash or restart
• Detect missed notifications from APP_DB to orchagent in SONiC systems that use redis-based communication channels
• Detect out-of-sync entries between APP_DB and ASIC_DB