Update boundary label styling to match Structurizr

Bigger title, smaller type indicator looks better than everything just
being plain bold text on the boundary border.

C4.puml

@@ -27,7 +27,6 @@ skinparam Arrow {
 skinparam rectangle<<boundary>> {
     Shadowing false
     StereotypeFontSize 0
-    FontSize 12
     FontColor #444444
     BorderColor #444444
     BorderStyle dashed
@@ -50,7 +49,7 @@ center footer <font color=red>Warning:</font> Created for discussion, needs to b
 ' ##################################
 
 !define Boundary(e_alias, e_label) rectangle "==e_label" <<boundary>> as e_alias
-!define Boundary(e_alias, e_label, e_type) rectangle "==e_label [e_type]" <<boundary>> as e_alias
+!define Boundary(e_alias, e_label, e_type) rectangle "==e_label\n<size:TECHN_FONT_SIZE>[e_type]</size>" <<boundary>> as e_alias
 
 ' Relationship
 ' ##################################