Include performance estimates in Condor JDLs

On the way to better provisioning, some of the splitters are able
to "predict" how long a job will take based on time per event estimates,
how much disk it will require based on estimates of output size per event
and how much memory the job will require. This information is included in
the condor JDLs in the following values:

+Wallclock_Time_Estimate
+Memory_Non_Swap_Estimate
+Disk_Space_Estimate

Subject to change after dicussion with the GlideIn team. The initial
idea included changing the estimates for time per event, size per event
and memory dynamically using couchDB information. However after giving some thought
I realized that with the current schema this is not useful and can be harmful. The case
is when the second block is split after only fast jobs have run, these will have
low time per event and memory usage which will trigger bad pilots for future jobs
and won't allow for correction.

The estimates will be only reliable in a model where we first fully process at least a block
before splitting the rest of the workload. This would give some guarantee that the sample
used for the performance information is somewhat representative.

Fixes #4472