[OpenTelemetry] Add Spring Boot dashboards to LGTM Dev Service

[ThomasVitale]

Use the Grafana API to load relevant default dashboards to the LGTM Dev Service.

[bsmahi]

Hi @ThomasVitale

Can I pick up this task

Thanks,
Mahi

[ThomasVitale]

@bsmahi thanks so much for your availability! If you want, the task is yours. I think the first step would be to investigate how to customize the ArconiaLgtmContainer so to load the Grafana CLI included in the image to load arbitrary dashboards during the startup phase.

For now, we can use resource mappings (see https://docs.arconia.io/arconia/latest/dev-services/#_resource_mappings) to mount some dashboard files from a given project, and have the ArconiaLgtmContainer react to that for customisation.