Bug 14826: Resurrect account offsets table

Bug 14826: Resurrect account offsets table

The account offsets table should be used to track increments and
decrements of fines via payments and credits, as well as fine accruals.
It should be able to match fees to payments and visa versa, so we can
know which fee was paid by a given payment, and which payments applied
to a given fee.

Test Plan:
1) Apply this patch
2) Run updatedatabase
3) Note the table accountoffsets has been renamed to account_offsets
4) Ensure fine generation creates offsets
5) Ensure creating a manual invoice creates an offset
6) Ensure a lost item charge creates an offset
7) Ensure Reverse Payment creates an offset
8) Ensure a payment creates an offset
9) Ensure a payment for multiple fees creates an offset for each
10) Ensure writeoffs create offsets

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>