feat(processors.converter): added support for base64 encoded ieee float32 types

[vkrasnici]

Summary

When using Cisco Telemetry MDT (cisco_telemetry_mdt) Input Plugin in combination with OpenConfig power Yang model (openconfig-platform:components/component/power-supply) the data is received but the power values are Base64 Encoded IEEE 754 Float32. The format received looks like below:

{"fields":{"data_json_content_state_openconfig-platform-psu:input-current":"QWAAAA==","data_json_timestamp":"1731938073759"},"name":"file","tags":{"host":"YJ4"},"timestamp":1732125250}
{"fields":{"data_json_content_state_openconfig-platform-psu:output-current":"QcAAAA==","data_json_timestamp":"1731938073763"},"name":"file","tags":{"host":"YJ4"},"timestamp":1732125250}
{"fields":{"data_json_content_state_openconfig-platform-psu:input-current":"QVAAAA==","data_json_timestamp":"1731938073766"},"name":"file","tags":{"host":"YJ4"},"timestamp":1732125250}
{"fields":{"data_json_content_state_openconfig-platform-psu:output-power":"RKeAAA==","data_json_timestamp":"1731938073773"},"name":"file","tags":{"host":"YJ4"},"timestamp":1732125250}

This makes the data unusable for metrics, as metrics should be represented by float/int (number). Using parser.json and parse_fields_base64 converts b64 to byte/str, but that's not enough to convert it to metrics, hence the motivation to add the converter support.

Checklist

• [x] No AI generated code was used in this PR

Related issues

Closes #16213

[telegraf-tiger[bot]]

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