Refactors `getNewValue` logic to replace it with an optional
`getPinnedValue()` where rangeStrategy=pin. This way each versioning
module doesn't need to add and test extensive "pin" logic.
This should not be breaking, but out of an abundance of caution, we'll
mark it as such.
Moves datasource, manager, platform and versioning code from lib/ into new lib/modules/
BREAKING CHANGE: External tools must update paths to datasource, manager, platform and versioning
Robert