Email reports in HTML: Updated styling to be consistent with new Custom Alerts emails design  (#11251)

* Updated Email Report/Downloaded Report. Added new styling found in the Alert Email. i.e navigation bar uptop, styled tables, added powered by piwik footer. Note: "back to top" link only works on downloaded version, not on the email.

* Fixed the back to top link not working in emails.

* Fixed a bug where logo was not centered in gmail

* Translations

* Code cleanup and making PDF generation work

* removed htaccess

* fix unit test

* Some test fixes

* UI Test