Reduce the number of workflow policies, as current 7 different are a bit confusing. Consider giving them better names.

There are 2 kinds of policies:

• those that stops executing (StopOnSuccess, StopOnError, StopOnSuccessOrError)
• those that always execute all tasks (other 4 policies)

It looks like at least 2 policies could be removed:
1. FinishAllAndError is the same as negated Group with FinishAllAndSuccess policy.
2. ContinueOnError is the same as negated Group with ContinueOnSuccess policy. When there is a task that finishes with Error, continueOnError reports error, while negated continueOnSuccess reports true.

Proposals for renamings:
StopOnSuccess -> AnySuccess
StopOnError -> AllSuccess
FinishAllAndSuccess -> AlwaysSuccess
ContinueOnSuccess -> ?
StopOnSuccessOrError -> StopOnFirstDone