Move nostr pubkeys to LDAP attribute

closes #173

db/migrate/20240316153558_remove_nostr_pubkey_from_users.rb

@@ -0,0 +1,5 @@
+class RemoveNostrPubkeyFromUsers < ActiveRecord::Migration[7.1]
+  def change
+    remove_column :users, :nostr_pubkey, :string
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2024_02_16_124640) do
+ActiveRecord::Schema[7.1].define(version: 2024_03_16_153558) do
   create_table "active_storage_attachments", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -129,7 +129,6 @@ ActiveRecord::Schema[7.1].define(version: 2024_02_16_124640) do
     t.string "unconfirmed_email"
     t.text "ln_password_ciphertext"
     t.string "ln_account"
-    t.string "nostr_pubkey"
     t.datetime "remember_created_at"
     t.string "remember_token"
     t.text "preferences"