Fully Genericize Version Command

[michaeltlombardi]

Once the version command is fully generic, it can be reused in other projects/apps, as build has been in PRM.

Acceptance Criteria

• Add a VersionCommand struct to the cmd/version/version.go which has the version, buildDate, commit, appName, and appSourceUrl properties.
• Add a VersionCommandI interface which must implement the CreateVersionCommand() and Format() functions
• Modify VersionCommand() to use the VersionCommand struct instead of parameters
• Modify the Format() function to use the VersionCommand struct instead of parameters and to not hard-code the application name
• Modify the changelogURL() private function to use the VersionCommand struct instead of parameters and to not hard-code the GitHub path