DataPackageManager: PASTA should ensure download URLs are properly encoded before attempting the download

[servilla]

PASTA should ensure download URLs are properly encoded before attempting the download.

[servilla]

The most appropriate location for this to occur is during the initial download attempt of the data entity. In this case, the URL encoding rewrite would occur dynamically as opposed to performing the encoding and rewriting the Level-0-EML content.

[servilla]

Appropriate processing sequence:

1. Attempt download with user-provided URL, and if fails
2. Encode URL and attempt again.

If failure occurs after second attempt (above), then a permanent failure will be registered and displayed.

Note, if the encoding becomes too onerous, just fail.

[servilla]

We should investigate whether a partial quality report can be generated if download URL failures occur, including more specific information about why the download failure occurred in the first place. Note that the first section of the quality report is only about the metadata correctness and would still provide good feedback to the user.