misleading metric names

[bastischubert]

hi there,

postfix_showq_message_size_bytes_count -> shows the count of messages in the queue and has nothing to do with either size nor bytes

you might want to rename that metric name

[BartVerc]

This is an automatic metric of Histograms with prefix _count.

[bastischubert]

Too bad you are ignoring prometheus best practices/recommendations on metric names.

I'll try a merge request instead ;)