Fix iga cache never matching any employees

The bug was caused by the iga at uib not saving the complete employee id with leading zeros. This meant that using the employee ids from the iga to create a mapping from employee id to iga object would never match the ids we have saved from DFØ-SAP. Adding back any removed leading zeros to the employee id when creating the mapping solves the problem, and is safe since we know that employee ids always are 8 digits long.

Perhaps not surprisingly, searching for a person in the iga using employee id with leading zeros does return the correct person, which means that the slow method of fetching one person at a times works.