examples: add example for using the SMTP module (#5870)

examples/smtp/mail.v

@@ -0,0 +1,40 @@
+// Creator: nedimf (07/2020)
+import os
+import net.smtp
+
+fn main() {
+	println('Hi, this is sample of how to send email trough net.smtp library in V, which is really easy using the net.smtp module.')
+	println('We are going to create a simple email client, that takes some arguments. and then sends email with an HTML body.')
+	println('To fully test email sending, I suggest using the mailtrap.io service, which is free and acts like a really nice mail server sandbox.')
+	println('')
+	println('V Email client')
+	println('')
+	mailserver := os.input('Mail server: ')
+	mailport := os.input('Mail server port: ').int()
+	println('Login')
+	username := os.input('Username: ')
+	password := os.input('Password: ')
+	from := os.input('From: ')
+	to := os.input('To: ')
+	subject := os.input('Subject: ')
+	body := os.input('Body: ')
+	client_cfg := smtp.Client{
+		server: mailserver
+		from: from
+		port: mailport
+		username: username
+		password: password
+	}
+	send_cfg := smtp.Mail{
+		to: to
+		subject: subject
+		body_type: .html
+		body: body
+	}
+	mut client := smtp.new_client(client_cfg) or {
+		panic('Error configuring smtp')
+	}
+	client.send(send_cfg) or {
+		panic('Error resolving email address')
+	}
+}