Removed an unused XSLT responsible for tailoring functionality

We do tailoring in the openscap API, duplicating that in XSLT increases
maintenance costs.
Deleted unused XSL files
Removed top navigation menu from HTML report
Added labels for progress bars displaying rule result breakdown
Initial support for check system result details

OVAL results are written out as docbook, this will be changed in future
commits.
Rewrite of oval-report.xsl to use HTML5 instead of docbook
Renamed oval-report.xsl to xccdf-report-oval-details.xsl to avoid confusion