Support to allow list packages for caching

[viditganpi]

There is a use case where we have setup a maxsize for caching of our packages, now their is a need to allow caching for some packages which exceed this max size.
In current implementation if these packages need to be cached then the maxsize property must be increased to accommodate these packages, but this will not only cache the required packages but also other non required packages.
The proposal is to introduce another property which when set can allow caching of packages irrespective of the max size.