docs: Add note for updated terminology (#11802)

# Which Problems Are Solved

For existing customers it could be hard to understand the new aligned
terms we have defined, if they are already used to the "old term"

# How the Problems Are Solved

Adding notes at the top of docs pages to state clearliy new and old
terms.

apps/docs/content/concepts/structure/administrators.mdx

@@ -6,6 +6,12 @@ sidebar_label: Administrators
 
 import AdministratorDescription from "./_administrator_description.mdx";
 
+<TerminologyUpdate
+    newTerm="Administrators"
+    oldTerms={["Members", "Memberships", "Managers"]}
+/>
+
+
 <AdministratorDescription components={props.components}  name="AdministratorDescription" />
 
 Notes:

apps/docs/content/concepts/structure/instance.mdx

@@ -4,6 +4,11 @@ description: "Overview of ZITADEL Instances—the virtual tenants providing full
 sidebar_label: Instances
 ---
 
+<TerminologyUpdate
+    newTerm="Instance"
+    oldTerms={["IAM"]}
+/>
+
 ## Instance Structure
 
 An instance is the top node in ZITADEL's data hierarchy.