[FEATURE] Numeric Scopes/Labels

**ECS integration/library project(s)**: Elastic.CommonSchema

**Is your feature request related to a problem? Please describe.**
E.g. I want to filter in Kibana for Scope properties like a "Duration" or something like that, to get all Requests that are higher than 1s. Right now, the property I log is of type keywoard with ECS, but with the Microsoft.Extensions.Logging.Console it's a number. So we loose that information.

**Describe the solution you'd like**
I'd like to have labels or scopes, that support numbers, not only string.

**Describe alternatives you've considered**
Is there already a way to do that with the current scheme? Or must this be solved on the filebeat level? Or even on the Index Template level?