mod_rest/openapi: Improve organization and navigation Properties roughly sorted by documentation first. GET paths sorted by complexity. Spacing to help with navigation. Some XML stuff that should arguably be a separate commit, but whatever. Tags.

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summary: Storage benchmark tool
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To benchmark `mod_storage_internal`:

    prosodyctl mod_benchmark_storage internal

Does a number (aprox. 10000) of reads and writes and to the selected
storage driver and tells you how long it took.