[FEAT] Job replacement option on duplicate contract address error

Description
If you add a job with a contract address that is already configured for an existing job, the Chainlink node throws an error. You then have to delete the conflicting job and add the new job. It would be a much better experience and decrease the chance of error if it simply prompted to replace the job. Ideally, this would work with the UI or the CLI (maybe a --force flag for the CLI).

Motivation
Over the past few months there have been many job replacement requests (multiple hundreds). This feature would eliminate half of the work for a node operator and decrease the possibility of removing incorrect jobs.

Justification
Another route would be to never have to replace a job, that is not very realistic.

Additional Information
Check out any node op's team slack channel for examples of replacement requests.

Start by tracing where duplicate contract addresses are rejected during job creation, then compare the existing UI and CLI entry points mentioned in the issue. Define whether replacement should be supported in one or both interfaces, including the proposed CLI force option; done means a conflicting job can be replaced without manual deletion and incorrect jobs are protected.