Call Dqlite remove endpoint for cleanup (KU-1719)

[HomayoonAlimohammadi]

Overview

This PR adds the logic to call the dqlite/remove endpoint upon node removal specifically to address issues with duplicate endpoints being found in the dqlite cluster when a new node is trying to join (and it's been allocated an IP which belonged to a now deleted node).

PRs regarding this feature:

• Calling the endpoint: Call node removal endpoint on machine deletion #66
• Minor fix to add /pkg to Dockerfile: Add pkg to Dockerfile and Fix TLS issue #67
• Adding auth header for validation: Add capi-auth-token header to /dqlite/remove request #68

[berkayoz]

LGTM