[SNMP] Improve the current Logstash Input

Describe the feature:
Improve SNMP input to be more easier to manage.

Describe a specific use case for the feature:
Currently, I am using SNMP input to poll from network devices. I find it a bit difficult to manage as with SNMP, you have a wide variety of OIDs to pull with different hosts with different credentials. This has led me to create a lot of different SNMP input Logstash configs. Would be great if there was a way to condense it.

Also, more "best practices" on translating OIDs into Elastic Common Schema. I am using custom fields like "snmp.ifOutErrors," but it would be great if Elastic offered more support in making snmp easier to use.

Also, working on retrieving tables using SNMP has made it complex to translate to ECS. I am currently using a split filter to ensure they can be indexed without using "snmp.0.ifOutErrors" and using "snmp.ifOutErrors" to make it easier for visualization.