Goal: 

• As a developer I want the backend service support /beta and /preview prefixes into the path.

Acceptance Criteria:

• Skippers works as expected when the path includes /beta or /preview for the different middlewares.
• Router wire paths for /beta /preview and no prefix.
• Metrics count the requests for /prefix and /beta paths.

TODO1: About metrics, should be considered as different counters? or count the same /prefix than /beta than no prefix? I mean GET /beta/api/hmsidm/v1/domains will increase the same counter as GET /api/hmsidm/v1/domains ? Something to consider.

TODO2: Related to TODO1, could the same deployment attend requests for no prefix, /beta and /preview prefixes? If no, the metrics are not mixed, else consider to label the metric, and store for the metric a normalized path (with no prefixes).