Azure functions overwite discover default service name

[rfavreau]

Hello team,

To fix the issue #2320 with the Service Name generated by the Azure Functions agent, i added a configuration OverwriteDiscoverDefaultServiceName item to be able to overwrite or not the service name.

So it will be possible to set the Service Name with the Artifact Name but also with the Azure Functions name. To not break the compatibility with the previous release, this setting is set to true and the Azure Functions name is set by default.

UnitTests and Documentation have been also updated.

Thank you for your approval.

Richard.