Issue with Dimension Label Naming Convention Causing Mismatch

[LarryLovestein]

Hello,

I have encountered an issue with the way new label dimensions are created in the azure-metrics-exporter. The current implementation uses the following code:
labelName := "dimension" + stringsCommon.UppercaseFirst(dimensionName)
This approach capitalizes the first letter of the dimension name, which leads to inconsistencies with other labels.

A better approach would be to use the following format:
labelName := "dimension_" + dimensionName

This would ensure consistency across all labels. Additionally, using this format allows for label mapping, enabling us to retain the original name of the label.

[LarryLovestein]

@mblaschke