The SAIP data format is inherently flat and doesn't intrinsically
have an idea of the tree-like structure of a filesystem. However,
if we want to (for example) convert a physical USIM into an eSIM
profile, we need to find the template for a given file, where the file
is identified by its path.
Let's expose a path property of the FileTemplate object, and populate
that when creating the FileTemplate as part of a ProfileTemplate.
Change-Id: Ie145ba159081daf8fbfa544f6d4248f05b7eea96
d2254377b6