This commits adds support for metrics dashboards
for embedding. If the flag 'embedded' is provided
to the environments/id/metrics_dashboard endpoint,
the response will be suitable for embedding in
issues or other content.
This is a precursor for support for embedding
metrics in GFM.
Adds a new stage to dashboard processesing step for the
EnvironmentsController::metrics_dashboard endpoint.
Allows the front end to avoid generating the endpoint
unitutive string mutations.
Updates the EnvironmentController#metrics_dashboard endpoint
to support a "dashboard" param, which can be used to specify
the filepath of a dashboard configuration from a project
repository. Dashboard configurations are expected to be
stored in .gitlab/dashboards/.
Updates dashboard post-processing steps to exclude custom
metrics, which should only display on the system dashboard.
