Require the storage to be explicitly set for persistent queue

[swiatekm]

Description:

The persistent queue needs a storage client to run. Currently, this simply takes the one storage extension defined, and errors if there are multiple available. This is both restrictive and arbitrary, and mostly works because it's currently unusual for users to define multiple storage extensions.

This change forces the users to explicitly set the storage extension in queue config if they want to use the persistent queue. This setting doubles as both choosing the storage and enabling the persistent queue - when storage: nil (the default), we use the in-memory queue, otherwise, we use the persistent queue with the set storage extension.

This was originally discussed in #5711, and it's part of that change. As it's a breaking change, I'd like to do it before we enable the persistent queue by default in the build.

Link to tracking Issue: Related to open-telemetry/opentelemetry-collector-contrib#10915

Testing:
Updated the unit tests.

Documentation:
Updated the queue readme.

[codecov]

Codecov Report

Merging #5784 (d66e1ff) into main (d146f29) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #5784   +/-   ##
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  Coverage   91.56%   91.56%           
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  Files         192      192           
  Lines       11470    11470           
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  Hits        10502    10502           
  Misses        773      773           
  Partials      195      195           

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[tigrannajaryan]

Shouldn't this be?

Suggested change

	storageID: "1",
	storageID: "file_storage/1",

I thought ComponentID always includes the component type name.

[swiatekm]

This is just a test parameter, in the actual test code we create numStorages storage extensions, and this is simply the index of the one we want to use in the test. I'll change it to storageIndex so it's less confusing.

[bogdandrutu]

Few suggestions:

1. Usually prefer to check for conditions first and return than indenting the code. if qCfg.StorageID == nil { return nil, nil }
2. Better to pass a non pointer ComponentID and then no need for the func to be on the QueueSettings. You already check for nil in the caller code.

[swiatekm]

Good point, thx. I also noticed I missed a test for the wrong extension type that was in my original PR, re-added while making these changes.

[bogdandrutu]

You need a rebase