Add new production installation script and related files

production/electrs-start-testnet

@@ -1,5 +1,5 @@
 #!/usr/local/bin/zsh
-cd $HOME/electrs
+cd "${HOME}/electrs"
 #source $HOME/.cargo/env
 #export PATH=$HOME/.cargo/bin:$PATH
 
@@ -13,11 +13,11 @@ do
 		--network testnet \
 		--address-search \
 		--cors '*' \
-		--db-dir /electrs \
-		--daemon-dir $HOME \
+		--db-dir __ELECTRS_DATA_ROOT__ \
+		--daemon-dir "${HOME}" \
 		--http-addr '[::]:3002' \
-		--cookie 'user:pass' \
-		--precache-scripts $HOME/electrs/contrib/popular-scripts.txt
+		--cookie '__BITCOIN_RPC_USER__:__BITCOIN_RPC_PASS__' \
+		--precache-scripts "${HOME}/electrs/contrib/popular-scripts.txt"
 
 	sleep 3
 done