Extend bootstrap header styles and update breadcrumb paths

- Move single variable from "structure" into file with other variables
"_theme.scss"
- Tidy alignment of theme.scss for easier scanning of colours

- Extend Bootstrap header class .page-header
- Use new .page-title class sitewide
- Add optional .with-border class for bordered titles

- Remove breadcrumb from organisation index page
- Rename "hits" to "analytics" in titles, breadcrumb and tabs
- Rename "count" to "hits" in hits table

- Fix position of logo within navbar on resize

- Update tests to reflect changes