Bug 29543: [19.11] Enforce authentication for self-checkout

Bug 29543: [19.11] Enforce authentication for self-checkout

The self-checkout feature is assuming a patron is logged in if patronid
is passed. It also assumes that "We're in a controlled environment; we
trust the user", which is terribly wrong!

This patch is suggesting to generate a JSON Web Token (JWT) to store in
a cookie and only allow action (renew, check in/out) is the token is
valid. The token is only generated once the user has been authenticated
And is removed when the user finish the session/logout.

Test plan:
You must know exactly how the self-checkout feature works to test this patch.
The 4 following sysprefs must be tested:
 SelfCheckoutByLogin, AutoSelfCheckAllowed, AutoSelfCheckID, AutoSelfCheckPass
Confirm that you can renew, checkin for the items you own, and checkout new items.
Confirm that you are not allowed to access other account's info.

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Bug 29543: Remove borrower variable

It's not needed, we have $patron

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Bug 29543: Remove inputfocus variable

It's not used in template

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Bug 29543: Add JWT token handling

Mojo::JWT is installed already, it's not a new dependency.
We need a way to send the patron a token when it's correctly logged in,
and not assumed it's logged in only if patronid is passed

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Bug 29543: Prevent user to checkin or renew items they don't own

Checkin or renew must be restricted to the items they own.

Test plan:
Create an item with barcode bc_1
Check it in to user A
Login to SCO with user B
Get the token using the browser dev tool, from the cookie
Hit (replace $JWT)
    /cgi-bin/koha/sco/sco-main.pl?jwt=$JWT&op=renew&barcode=bc_1
    /cgi-bin/koha/sco/sco-main.pl?jwt=$JWT&op=returnbook&barcode=bc_1

You should see an error message

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Bug 29543: (follow-up) Add a warning to SelfCheckoutByLogin

This updates the language to warn users of risk if using cardnumber for login and auto-self-check is enabled

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Bug 29543: Add Mojo::JWT dependency

Bug 29543: Set autocomplete off for SCO login fields

Cardnumber already had it set, adding for username and password

Signed-off-by: Wainui Witika-Park <wainuiwitikapark@catalyst.net.nz>