Improve error message when Berksfile.lock versions not found on `berks install`.

Addresses #1221
Improves invalid cookbook/versions in Berksfile.lock with better error messages.
[CR] Consolidate error types for missing cookbook version from Berksfile.lock.
[CR] Rename InvalidLockfileCookbookVersion to MissingLockfileCookbookVersion.
[CR] Improve comment on new missing version from Berksfile.lock in Installer.
[CR] Remove use of 'lockfile' and improve Scenario descriptions.
[CR] Remove Berksfile#versions_for as no longer necessary.
[CR] Update old v2 Berksfile.lock format to v3.