Add SSH keys to deploy-setup

This helps me set up new devices, while still keeping passworded SSH access locked down!

deploy/authorized-ssh-keys.txt

@@ -0,0 +1,16 @@
+# These are the SSH public keys that allow a user to log in and setup or deploy.
+#
+# It's dangerous to add a new key to this file! When you run
+# `yarn deploy-setup`, it will copy these keys to the deploy server, which will
+# allow the owner of these keys to log into the deploy server in the future.
+#
+# But the keys themselves aren't necessarily sensitive data, except for the name
+# at the end, which might tell a reader about who is allowed to log in and what
+# devices they own.
+#
+# When a computer tries to log in, it perform a cryptographic challenge that
+# proves it owns this key - but that requires the *private* key, whereas this is
+# the *public* key. That's why it's secure to publish these!
+
+ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAID2/yLvpetD14BVK+Zd88ZofOxIfLRdl4FI2pdV+fmy3 Matchu's Desktop (Leviathan) WSL
+ssh-rsa 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 Matchu's Laptop (Ebon Hawk)

deploy/playbooks/setup.yml

@@ -4,6 +4,11 @@
   vars:
     email_address: "emi@matchu.dev" # TODO: Extract this to personal config?
   tasks:
+    - name: Copy authorized SSH keys
+      copy:
+        dest: ~/.ssh/authorized_keys
+        src: ../authorized-ssh-keys.txt
+
     - name: Disable root SSH login
       become: yes
       lineinfile: