lib: Generate driver IDs, instead of hard-coding them

Instead of adding driver IDs by hand to a header file, generate the
driver ID from the (hopefully unique) name of the driver.

This means one file less for driver authors to modify, and one possible
source of merge conflicts less as well.

However, this means that already enrolled fingerprints will need to be
enrolled again, as the driver IDs will have changed compared to their
old on-disk value.

doc/advanced-topics.xml

@@ -71,10 +71,7 @@
     <title>Driver IDs</title>
 
     <para>
-    Each driver is assigned a unique ID by the project maintainer. These
-    assignments are
-    <ulink url="https://gitlab.freedesktop.org/libfprint/libfprint/blob/master/libfprint/drivers/driver_ids.h">
-    documented in the sources</ulink> and will never change.
+    Each driver is assigned a unique ID automatically based on the driver name.
     </para>
 
     <para>