Add probe indirection for probe management

This allows to enable/disable and list probes either internally or through
REST.

• GET /instrumentation_probe_search/all

Will return the list of currently defined probes in the running instance

• PUT /instrumentation_probe_search/unused

Will enable all probes

• DELETE /instrumentation_probe_search/unused

Will disable all probes

Signed-off-by: Brice Figureau <brice-puppet@daysofwonder.com>