Complete rewrite of the removal policy list, to work along the

Complete rewrite of the removal policy list, to work along the
same lines as the filesystem list. Now a list of calls to
storeReplAdd() is generated, which adds the policies to a dynamic
list, and storeCreateRemovalPolicy searches this list for the
requested policy name.

This also allows for a seemless integration of loadable modules
at any time. All that is needed to have filesystems or policies
in loadable modules is to write the few lines of code required
to bring in the shared object, and to call the appropriate
registering function (storeFsAdd or storeReplAdd).