Added REST API endpoints for indicator management:
* GET /v1/nodes/<node_ident>/management/indicators` to list all
available indicators names for each of the hardware component.
* GET /v1/nodes/<node_ident>/management/indicators/<indicator_ident>
to retrieve the state of given indicator.
* PUT /v1/nodes/<node_ident>/management/indicators/<indicator_ident>`
change state of the desired indicator.
This implementation slightly deviates from the original spec in
part of having component name in the URL - this implementation
flattens component out.
The spec: https://review.opendev.org/#/c/655685/7/specs/approved/expose-hardware-indicators.rst
Change-Id: I3a36f58b12487e18a6898aef6b077d4221f8a5b8
Story: 2005342
Task: 30291
263fd021b2