Bug 14776: Remove 'selfcheck' patron related links from and add language selector...

Bug 14776: Remove 'selfcheck' patron related links from and add language selector to SCO header

The SCO screen displays patron related menu items in it's header (Link to the account and "Logout").
This makes no sense since the patron that is logged in is the 'selfcheck' user as defined in syspref AutoSelfCheckId.
Additionally, the language menue is missing when the syspref OpacLangSelectorMode is set to 'top' or to 'both'.

To test:
- Apply on top of Bug 15039
- Set AutoSelfCheck sysprefs as appropriate
- Set OpacLangSelectorMode to 'top' or 'both'
- Go to SCO page
- Verify that the language menue does not display in the header
- Enter a card number to check out (this logs in the SCO user)
- Verify that you get text similar to "Welcome, checkout" with a link to the sco user's account in the OPAC and a 'Logout' link
- Apply patch
- Verify that the language menu appears and the SCO user's information disappears.
- Verify, that the language menu displays / does not display with combinations of:
  - opaclanguagedisplay (Allow)
  - opaclanguages ( > 1 language selected)
  - OpacLangSelectorMode (top or both)

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>