Insure roundtrip of exact version string by not making Version.version a property

In pins, there is (potentially) relevant version information stored at two levels.

• version name: this is the component of the actual path to the data. e.g. <some_board>/<pin_name>/<version_name>.
• data.txt file: has entries pin_hash and created.

In the current pins implementation the version name is a function of the info in the data.txt file. However, because the version name is important for specifying where a pin is, I would avoid deriving it from created and pin_hash. At the point that we pull data.txt, we know exactly what version name is...!

Right now, there is a Version.version property that calculates it from created and pin_hash. Let's allow that attribute to be set independent of those two things.....

Start by locating the Version implementation and the code that reads data.txt, then trace how the version name is recovered from stored metadata. Verify how an exact version name is lost during a round trip and identify the existing tests around version handling. Done means the original version name survives independently of created and pin_hash.