Add export

[matthewhilton]

Changes

• Adds table_sql's built in downloading function, allowing users to download the report:

As part of this:

• The URIs are fully expanded in download mode (truncated normally)
• The action column is empty when exporting (to avoid accidental clicking to delete result in HTML export). While it would be ideal to remove the column altogether, it is far simpler code-wise with the current layout of the page to just simply make it empty.

Testing

Manual testing:

1. Enabled CSP headers in plugin settings
2. Went to CSP test page, this generates csp reports
3. Went to CSP report page, downloaded main report, works as expected
4. Drilled down into CSP reports by clicking on number at start of one of the rows
5. Downloaded drill-down report, works as expected

Main export	Drill down export