Implement metrics denylist

[almirmcunhajr]

The exporter metrics cardinality exceeds 30k, and we don't need some metrics to be exported. A metrics denylist may help us to take more control over the cardinality.

The strategy is to not auto-register metrics when declaring, and register only when not presented in the denylist.

For the future, we should consider using a custom collector to follow the good practices as explained here: https://prometheus.io/docs/instrumenting/writing_exporters/#collectors

[varuzam]

when is it going to be merged ?