Replace the input! macro with an Input builder (#646)

* Replace the input! macro with an Input builder

* Use a BTreeMap instead of an HashMap

Followinf @fdb-hiroshima's advice

* Rename Input::to_html to Input::html

To make clippy happy

* Wrap error messages in red paragraphs

templates/session/password_reset_request.rs.html

@@ -9,7 +9,12 @@
   <h1>@i18n!(ctx.1, "Reset your password")</h1>
 
   <form method="POST">
-    @input!(ctx.1, email (email), "E-mail", form, errors.clone(), "minlenght=\"1\"")
+  	@(Input::new("email", i18n!(ctx.1, "Email"))
+  		.default(&form.email)
+  		.error(&errors)
+  		.set_prop("minlenght", 1)
+  		.input_type("email")
+  		.html(ctx.1))
     <input type="submit" value="@i18n!(ctx.1, "Send password reset link")" />
   </form>
 })