Remove unused config params

[artlowel]

References

• Fixes an issue mentioned in a comment of #3124

Description

This PR removes the config properties rewriteDownloadUrls and logDirectory because they are no longer used.

It also fixes the getRequestOrigin() method in ServerHardRedirecService: it used to return the host, not the origin. I've renamed the method and updated the typdocs to make its purpose clearer.

Instructions for Reviewers

You can verify that the origin is correct by checking e.g. the citation_pdf_url meta tag on an item page while javascript is disabled. It should now contain both the scheme and the port.

Checklist

• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes TSLint validation using yarn run lint
• My PR doesn't introduce circular dependencies
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• If my PR includes new, third-party dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.

[tdonohue]

👍 Looks correct & it works for me. Thanks @artlowel for the quick fixes & the improvements here. Merging immediately as these are minor changes, but necessary for 7.0