#244 Add sprites robot and robot2

[kirchsth]

implementation of #244

Sprites and other images

C4-PlantUML offers predefined person and robot sprites which can be directly used:

• person,person2
• robot, robot2

@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Component.puml

Person(pB, "Sam", $sprite="person2")
Person_Ext(pA, "Bob", $sprite="person")

System_Ext(robB, "Robot A", $sprite="robot2")
System_Ext(robA, "Robot B", $sprite="robot")

SHOW_LEGEND()
@enduml

It can be tested with my extended branch

@Potherca: should I add the following sample with a robot specific legend to the readme.md too (but I think it could be too confusing without explanation)

BR Helmut

@startuml
!include https://raw.githubusercontent.com/kirchsth/C4-PlantUML/extended/C4_Component.puml

AddPersonTag(admin, $legendText="admin", $sprite="person2")
AddExternalPersonTag(user, $legendText="user", $sprite="person")

AddExternalSystemTag(cleanroomRobot, $legendText="cleanroom robot", $sprite="robot2")
AddExternalSystemTag(humanoidRobot, $legendText="humanoid robot", $sprite="robot")

Person(pA, "Person A", $sprite="person", $tags="user")
Person_Ext(pB, "Person B", $sprite="person2", $tags="admin")

System_Ext(robA, "Roboter A", $tags="humanoidRobot")
System_Ext(robB, "Roboter B", $tags="cleanroomRobot")

SHOW_LEGEND()
@enduml

[Potherca]

Nice work! Merging this.