Some simplifications to the Ivy and Maven metadata parsing. Don't extract and persist the `description` and `publicationDate` properties for Ivy and Maven as these values are not required for dependency resolution. Incremented the cache version to reflect this change. Removed some dead code that attempted to include a `description` in a generated ivy.xml, as there is no way to specify this in the Gradle DSL.
Moved some Maven metadata properties from constructor parameters to mutable properties.