Add possibility to customise worker process `labels` and `Name` (wid)

[duksis]

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First of all thanks for the great library - your work is highly appreciated! 🙏

With this issue I would like to suggest an enhancement - ability to customize the worker labels and name or (wid).

Background: I have a project with multiple worker applications connecting to the Faktory server and performing work. Currently I'm having trouble identify which process belongs to which application/deployment when using the UI because wid is not descriptive and the single label of elixir-1.x.x is in most case not helpful either. currently these values do not seem to be configurable https://github.com/opt-elixir/faktory_worker/blob/e322cd644cde2baa867465d9093f16bca1f60352/lib/faktory_worker/connection.ex#L128

[Ch4s3]

I'm open to a PR on this.

[duksis]

@Ch4s3 #207 adds the possibility to configure labels, name can be set indirectly by changing the hostname of the instance that is running the worker.