Implement quote suggestion form

It will accept new quotes from captcha-approved users and put the quotes to the `queued_quote` table. There is also an `author` field that will contain the author IP address (or something alike).

It uses reCaptcha service that requires registration. I've already registered and I will fill the reCaptcha configuration parameters on our production server.
I'd place it to `security` package. But it's ok for now.