Split sample PKI token generation

Splits the file that generates the sample data into two.
One part is the set of individual functions.  The second
is a script that calls each of the functions in turn.  By
splitting them, it becomes easier to regenerate just a subset
of the sample data.  The use-case that prompted this change
was the need to regenerate the signed tokens based on a different
algorithm.  Without this change, all of thecertificates would
need to be regenerated, and that has nothing to do with the
actual change required.

Change-Id: I53b6cfde98a52f0a59b06ad8abbe0d2f1251f796
Merge "Split sample PKI token generation"