Bug 34397: Fix inconsistencies in Classification sources page titles, breadcrumbs...

Bug 34397: Fix inconsistencies in Classification sources page titles, breadcrumbs, and headers

This patch fixes some inconsistencies in the classification
configuration administration page, making sure the page title,
breadcrumb navigation, and page headers are consistent with each other.

Test each view to confirm that page title, heading, and breadcrumbs are
consistent:

- Administration -> Classification configuration
  - New classification source
  - Edit classification source
  - New filing rule
  - Edit filing rule
  - New splitting rule
  - Edit splitting rule

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>