Bug 20260: Use CodeMirror for the SQL reports editor

Bug 20260: Use CodeMirror for the SQL reports editor

This patch adds CodeMirror syntax highlighting to the SQL reports
editor. Newly added is a file containing the sql-specific syntax
highlighting code, in both compressed and uncompressed versions.

Unrelated changes:

 - Some JavaScript has been moved from inside the body of the page to
   the footer.
 - Paths to some assets have been corrected to no use relative paths.

To test, apply the patch and go to Reports -> Saved SQL reports

- Edit an existing report and confirm that the SQL is correctly
  highlighted and that there are no display problems when editing.
- Confirm that changes are saved successfully.
- Perform the same test when creating a new SQL report.
- View an existing report and confirm that the SQL is syntax-highlighted
  but is read-only.

Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>