accounts, cmd, internal, signer: add note about backing up the keystore (#19432)

* accounts: add note about backing up the keystore

* cmd, accounts: move the printout to accountCreate

* internal, signer: add info when new account is created via rpc

* cmd, internal, signer: split logs

* cmd/geth: make account new output a bit more verbose

cmd/geth/accountcmd_test.go

@@ -74,8 +74,18 @@ Your new account is locked with a password. Please give a password. Do not forge
 !! Unsupported terminal, password will be echoed.
 Passphrase: {{.InputLine "foobar"}}
 Repeat passphrase: {{.InputLine "foobar"}}
+
+Your new key was generated
+`)
+	geth.ExpectRegexp(`
+Public address of the key:   0x[0-9a-fA-F]{40}
+Path of the secret key file: .*UTC--.+--[0-9a-f]{40}
+
+- You can share your public address with anyone. Others need it to interact with you.
+- You must NEVER share the secret key with anyone! The key controls access to your funds!
+- You must BACKUP your key file! Without the key, it's impossible to access account funds!
+- You must REMEMBER your password! Without the password, it's impossible to decrypt the key!
 `)
-	geth.ExpectRegexp(`Address: \{[0-9a-f]{40}\}\n`)
 }
 
 func TestAccountNewBadRepeat(t *testing.T) {