#211 AddProperty for relationships

[kirchsth]

Implementation of #211

Properties can be added to relationship too like below

@startuml
!include https://raw.githubusercontent.com/kirchsth/C4-PlantUML/extended/C4_Deployment.puml

' default header Property, Value
AddProperty("Name", "Flash")
AddProperty("Organization", "Zootopia")
AddProperty("Tool", "Internet Explorer 7.0")
Person(personAlias, "Label", "Optional Description (with default property header)")

SetPropertyHeader("Property","Value", "Description")
AddProperty("Prop1", "Value1", "Details1")
AddProperty("Prop2", "Value2", "Details2")
Deployment_Node_L(nodeAlias, "Label", "Optional Type", "Optional Description (with custom property header)") {

  WithoutPropertyHeader()
  AddProperty("PropC1", "ValueC1")
  AddProperty("PropC2", "ValueC2")
  Container(containerAlias, "Label", "Technology", "Optional Description (without property header)")
}

System(systemAlias, "Label", "Optional Description (without properties)")

' starting with v.2.5.0 relations support properties too
WithoutPropertyHeader()
AddProperty("PropC1", "ValueC1")
AddProperty("PropC2", "ValueC2")
Rel(personAlias, containerAlias, "Label", "Optional Technology", "Optional Description")
@enduml

Additional C4Version() is changed to 2.5.0beta1 too.

It can be tested with my extended branch

BR Helmut