Add ceph-exporter to service placement interface

[UtkarshBhatthere]

Description

Adds ceph-exporter daemon to service placement interface

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• New functional test which enables and performs a curl test on the ceph-exporter metrics endpoint

Contributor's Checklist

Please check that you have:

• self-reviewed the code in this PR.
• added code comments, particularly in hard-to-understand areas.
• updated the user documentation with corresponding changes.
• added tests to verify effectiveness of this change.