take apart systemd installation and refresh links and readme

electrs/2_electrs_systemd_service.sh

@@ -0,0 +1,35 @@
+# Install the electrs systemd service.
+# Prerequisite: 1_electrs_on_RaspiBlitz.sh
+
+# To download and run:
+# $ wget https://raw.githubusercontent.com/openoms/bitcoin-tutorials/master/electrs/2_electrs_systemd_service.sh && bash 2_electrs_systemd_service.sh
+
+echo ""
+echo "***"
+echo "Type the PASSWORD B of your RaspiBlitz followed by [ENTER] for the electrs service:"
+read PASSWORD_B
+
+# sudo nano /etc/systemd/system/electrs.service 
+echo "
+[Unit]
+Description=Electrs
+After=bitcoind.service
+
+[Service]
+WorkingDirectory=/home/admin/electrs
+ExecStart=/home/admin/electrs/target/release/electrs --index-batch-size=10 --jsonrpc-import --db-dir /mnt/hdd/electrs/db  --electrum-rpc-addr="0.0.0.0:50001" --cookie="raspibolt:$PASSWORD_B"
+
+User=admin
+Group=admin
+Type=simple
+KillMode=process
+TimeoutSec=60
+Restart=always
+RestartSec=60
+
+[Install]
+WantedBy=multi-user.target
+" | sudo tee -a /etc/systemd/system/electrs.service 
+
+sudo systemctl enable electrs
+sudo systemctl start electrs