Move testnet ssh key (#5770)

* Factor out hardcoded testnet ssh key path

* Build/create test net ssh key path

* Rename testnet ssh dir

* Give testnetSSHDir a more generic name

* shellcheck

* favor hardcoded paths over `paths.sh`

* Put instance-startup-complete stamp in the scratch dir as well

* Rename `/solana` > `/solana-scratch`

net/scripts/add-testnet-solana-user-authorized_keys.sh

@@ -6,8 +6,6 @@ set -ex
 
 [[ -d /home/solana/.ssh ]] || exit 1
 
-
-
 if [[ -z $SOLANA_PUBKEYS ]]; then
   echo "Warning: source solana-user-authorized_keys.sh first"
 fi
@@ -15,9 +13,9 @@ fi
 # solana-user-authorized_keys.sh defines the public keys for users that should
 # automatically be granted access to ALL testnets
 for key in "${SOLANA_PUBKEYS[@]}"; do
-  echo "$key" >> /solana-authorized_keys
+  echo "$key" >> /solana-scratch/authorized_keys
 done
 
 sudo -u solana bash -c "
-  cat /solana-authorized_keys >> /home/solana/.ssh/authorized_keys
+  cat /solana-scratch/authorized_keys >> /home/solana/.ssh/authorized_keys
 "

net/scripts/create-solana-user.sh

@@ -13,15 +13,15 @@ else
   echo "solana ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers
   id solana
 
-  [[ -r /solana-id_ecdsa ]] || exit 1
-  [[ -r /solana-id_ecdsa.pub ]] || exit 1
+  [[ -r /solana-scratch/id_ecdsa ]] || exit 1
+  [[ -r /solana-scratch/id_ecdsa.pub ]] || exit 1
 
   sudo -u solana bash -c "
     mkdir -p /home/solana/.ssh/
     cd /home/solana/.ssh/
-    cp /solana-id_ecdsa.pub authorized_keys
+    cp /solana-scratch/id_ecdsa.pub authorized_keys
     umask 377
-    cp /solana-id_ecdsa id_ecdsa
+    cp /solana-scratch/id_ecdsa id_ecdsa
     echo \"
       Host *
       BatchMode yes