[enhancement]: Allow substitutions on process name

[commi235]

Feature description

Process Name should be able to pick up any substitutions from process variables.
For this we add a new attribute on process/collaboration which takes the default process instance name.
When called via flow_create one can still overwrite the default but parameter pi_prcs_name will be changed to optional.
On flow_start the engine will take the given process name and run it through process variable substitution.
This way we can allow better dynamic process instance names while still retaining previous behaviour.

This also links to Message Start Events, those need an easy way to set process variables when triggered.
This needs to happen before the flow_start call, so above substitution also works there.
see #687 for details on that.

Describe alternatives you've considered

No response

Additional context

No response

[rallen2010]

With msg flow start events creating processes, this becomes important. Should also look at this for user tasks.