Add tasks for modifying schema, first custom attributes

refs #172, #173

schemas/ldap/nostr_key.ldif

@@ -0,0 +1,9 @@
+dn: cn=schema
+changetype: modify
+add: attributeTypes
+attributeTypes: ( 1.3.6.1.4.1.61554.1.1.2.1.21
+  NAME 'nostrKey'
+  DESC 'Nostr public key'
+  EQUALITY caseIgnoreMatch
+  SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
+  SINGLE-VALUE )