Include performance parameter in workload

First part of #4472, include the performance information that is now already
required but only stored in the schema. The performance information is stored by
task and can be different depending on the type of task. For top level tasks
it uses all values specified by the requestor, for auxiliary tasks it uses
a time estimate of 8h that can be tuned through a request injection parameter
although usage is not expected really as these estimates will be probably
coarse grained where 8h should be the min job length.

Tasks like skims and second step TaskChain use their own estimate which is optional
and defaults to the top level value.

Merge tasks store the size per event only in order to detect disk values going too high.

This is only the ReqMgr and Workload definition changes. After this we need the changes at the
agent level in the splitters but that is independent of cmsweb schedule.