[cmd/opampsupervisor]: Refactor NewSupervisor to take a config instead of a filepath

[BinaryFissionGames]

Component(s)

cmd/opampsupervisor

Describe the issue you're reporting

The supervisor currently takes in a path to a config file. https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/20d6bae9ee577822cc72301d1eea4cfbd909040a/cmd/opampsupervisor/supervisor/supervisor.go#L141

Instead, it should take in a config struct (this config can be read from disk in main). This makes it easier to unit test and easier to use as a library, since the config would not need to be written to disk in order to run the supervisor.

[github-actions[bot]]

Pinging code owners:

• cmd/opampsupervisor: @evan-bradley @atoulme @tigrannajaryan @BinaryFissionGames

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[crobert-1]

Removed needs triage as this makes sense to me, was filed by a code owner, and another code owner responded with +1.