K8S Processor: record-level tagging

[pmm-sumo]

Is your feature request related to a problem? Please describe.
For some sources (e.g. logs coming via fluentforward protocol) it is common that attributes are present at record-level only. Those attributes can include important information used for K8s tagging, such as the IP address of the source that yielded the record. Perhaps the processor could be enhanced with capability to do tagging at a record-level, rather than only resource-level.

Describe the solution you'd like
Extra configuration parameter that enables tagging at a record-level (when no information is found at resource-level), e.g.

• record_level_tagging_enabled - by default: false

Describe alternatives you've considered
There are at least two alternative solutions:

• always trying to tag at record-level attributes when tagging was not possible at resource-level attributes due to missing IP information (i.e. no extra configuration necessary)
• if resource-level attributes are empty, grouping the records by record-level IP attribute (if present) and extracting the IP (and possible other common fields) into the resource-level (which can be done by a separate processor, e.g. groupbyattributesprocessor, akin to groupbytraceprocessor)

Additional context
This problem can be generally present for sources that originally do not have the concept of resource attributes, e.g. Zipkin spans or logs coming through fluentforward protocol

[pmm-sumo]

A better solution is to use: open-telemetry/opentelemetry-collector#1884