Bug 32310: Correct CSS in the staff interface which still uses old color scheme

Bug 32310: Correct CSS in the staff interface which still uses old color scheme

This patch updates staff interface CSS so that it better conforms to the
color scheme of the updated staff interface.

To test, apply the patch and rebuild the staff interface CSS.

- Go to Tools -> Calendar. Corrected are the borders around the calendar
  and around the "Add new holiday" panel which appears when you click a
  date on the calendar.
- Go to Patrons and perform a search which will return multiple results.
  - Check the checkbox for some patrons. The color of the "Patrons
    selected" box have been updated.
  - Incorrect padding values have also been removed from the adjacent
    patron list and merge buttons.
- Locate a multi-paged DataTable, e.g. Administration -> Authorized
  values. The style of the "Next" and "Previous" buttons have been
  updated.
- View a patron record and choose More -> Set permissions from the
  toolbar. In the table of permissions, when you hover your mouse over
  one of the headings ("Check out and check in items," "Edit
  authorities," etc.) the color should be correct.
- I don't think this is ever visible in the staff interface, but the
  template has markup in it to display a "Log in" link in the header
  menu if the user isn't logged in. I've removed some redundant CSS
  corresponding to this link and corrected some markup just in case
  there is a situation in which is appears.

Signed-off-by: Amit Gupta <amitddng135@gmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>