In the PC/SC world, each slot is associated with a string name. In the
bankd for PC/SC readers, we need to establish a mapping which
bank_id/slot_nr maps to which given string name. We use a minimalistic
CSV file for defining those mappings. The file is read only once at
bankd startup time.
Change-Id: Ifd2caab670625e2e3fbc57b966dce2f43b690417