Add NREN level puml files

Federation_Registry.puml

+@startuml nren_registry_flow
+title NREN Registry flow
+entity "Leaf\nEntity" as leaf
+entity NREN as nren
+database Subordinates as subs
+
+leaf -> nren: Express interest joining
+nren -> nren
+note right
+ Check if not
+ in Subordinates
+end note
+nren --> leaf: Ask Leaf to 
+note left
+ - Accept Policy
+ - Comply with Technicalities and Security
+end note
+leaf -> nren: Acceptance
+nren --> nren
+note right
+Manualy Check 
+Accecptance
+of Leaf entity
+end note
+nren --> leaf:Issue TM
+note left
+Leaf entity Adds TM to configuration
+end note
+
+leaf -> nren: Go to enroll endpoint
+nren -> subs: Add leaf entity to subordinates
+
+@enduml
\ No newline at end of file

Federation_Registry_Classes.puml

+@startuml NREN
+title NREN Registry
+
+class Leaf {
+-RP
+-OP
+-...
+}
+
+class Nren {
+-Public Policy
+-List of Subordinates
+-Resolve endpoint
+-Enroll endpoint
+-TM endpoint
+-TM list
+-TM status
+}
+
+class Subordinates {
+ -Accepted Policy of NREN
+ -Comply with technical and Security
+ -Manualy checked by NREN and given a TM 
+}
+
+@enduml
\ No newline at end of file