Summary: Added rpc to node agent to turn on/off already installed earlyoom service

Test Plan: this diff is a part of a big diff where the whole cycle of installing + turning on/off via rpc was tested

Reviewers: nsingh, anijhawan

Reviewed By: nsingh, anijhawan

Subscribers: yugaware

Differential Revision: https://phorge.dev.yugabyte.com/D42209