Consider logging and error reporting for WordPressShared and UserAgent

[mokagio]

#24216 extracts WPUserAgent to WordPressShared to enable sharing it with other modules. Whether or not modules should access it is debatable, but that's the state of the code we have at the moment and it's convenient to play along in the interest of laying the foundation to quickly prototype the dedicated Reader app.

Part of the work included adding CocoaLumberjack as a dependency in WordPressShared, but this resulted in some of the tests crashing because of compilation issues.

Given the whole idea of having a logging library in WordPressShared was debatable, #24216 (comment), and because of the focus in establishing support for Reader, I decided to simply remove the dependency via f95be44 instead of figuring out where the issue was.

This is a bread crumb to remind us to go back and find out.

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See also #24165

[dangermattic]

Thanks for reporting! 👍