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
Create a test token generator and use it

All the clients are currently storing samples of keystone tokens so that
they can use them in testing. This is bad as they are often out of date
or contain data that they shouldn't.

Create a V2 Token generator and make use of that for generating tokens
within our tests.

Change-Id: I72928692142c967d13391752ba57b3bdf7c1feab
blueprint: share-tokens
Merge "Split sample PKI token generation"