Refactor to support magic namespace require with language context annotation

[dgtized]

Per my comment in https://github.com/clojure-emacs/clj-refactor.el/pull/521#issuecomment-1179577092, this PR makes no changes in the current behavior, but extracts and breaks up the current logic to facilitate using a defcustom in a later PR to select the magic require logic. In addition, it adds test coverage for each the methods extracted. My intention is to rebuild the changes in #521, as a sequence of commits on top of this. My hope is if this is merged, we can introduce a defcustom feature flag inside of cljr-slash, that will re-use some of these helpers but will otherwise be an independent change.

For review, I would recommend going through the first 3 commits step by step as they are clean changes, everything after I can squash as a single commit if preferred as they are just adding test coverage to the extracted methods.

Thanks in advance for your review!

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Thanks!

[vemv]

Thanks much for the splitting! I'll review tomorrow-ish

[dgtized]

I believe I addressed all concerns in the latest push. Let me know if anything else needs to be addressed.

[vemv]

Excellent!