Adds the capability to request a Slot Verification when an inventory is
'Pending to Approve'. When asked from an inventory adjustment, which have
discrepancies over the threshold for the location, a Slot Verification
Request will be created for each line that exceed the maximum discrepancy
allowed.

A SVR must be created when warehouse operation (e.g. an inventory adjustment,
a cycle count...) uncovers a count discrepancy within a slot (a small stock
location), and the discrepancy is greater than the pre-defined acceptable
variance threshold. It is a stock manager's task to confirm the SVR and
assign it to someone to perform it.

The aim of SVR is to find and fix errors before they are transferred to
another location, so they will not be found again in similar stock operations.
In other words, a SVR helps to correct an already existing error in our stock
records the earliest possible. Many times, a SVR will likely lead to manual
actions (before being marked as solved) in order to fix the problems uncovered.
