Add osquery_version to all logs

[RebeccaMahany]

We are finding that it would be useful to include the osquery version in logs, the same way that we do for launcher_version.

This issue has two parts.

First, we should make the osquery version available in the knapsack. Similar to the InModernStandby flag, this flag should not be set by the command-line options -- it should only be set by launcher itself. We should have the osquery runner check the version and set it, after starting up the osquery instance. This will allow us to set the version correctly a) on launcher startup and b) on osquery autoupdate, when the osquery instance is restarted. There is an example for performing a version check here during launcher startup.

Second, we should include this version, when available, when shipping logs. The relevant logshipping code is here.