Bug 25630: Fix capitalization and terminology for Enhanced content and Web services...

Bug 25630: Fix capitalization and terminology for Enhanced content and Web services system preferences

- Fixes capitalization, including URL and OPAC
- Consistent use of "staff interface"
- Ending punctuation
- Spelling: web service

To test:
- Verify:
  - Enhanced content page heading
  - Babeltheque_url_js
  - Babeltheque_url_update
  - FRBRizeEditions
  - BakerTaylorEnabled
  - NovelistSelectStaffProfile
  - NovelistSelectStaffEnabled
  - CustomCoverImages
  - LocalCoverImages
  - IntranetCoce
  - AutoShareWithMana
  - OAI-PMH:AutoUpdateSets
  - IdRef
- read correctly.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>