Bug 32221: Borrowers.password should no longer be an option

Bug 32221: Borrowers.password should no longer be an option

When creating a notice template the user has the option to add the borrower's
password to the template. This should be removed as the password should not be
an option to be added to a notice.

Test plan:
1) Navigate to Tools > Notices and slips
2) Either create a new notice or edit an existing notice
3) Observe that in the list of fields available to insert into the message body,
   there is the option for "borrowers.password"
4) Apply patch
5) Navigate to the same menu
6) Observe that the "borrowers.password" option is now no longer visible

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>