Bug 24456: change default sort orders/make wording clearer

Bug 24456: change default sort orders/make wording clearer

TEST PLAN:
1. Apply patch
2. Have some checkout from today and some from multiple previous days.
3. Set todaysIssuesDefaultSortOrder & previousIssuesDefaultSortOrder to 'earliest to latest' and confirm it sorts correctly.
4. Reverse the 2 system preferences and see that it is now sorting the opposite way.
5. Also look at the wording of each system prefence and make sure it makes sense

Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>