Convert "Feedback" link to a contact us form

[peetucket]

email address is [email protected]

Per Tom: can be modeled on other projects like searchworks' feedback form, which pops down and sends to email (with captcha).

[jcoyne]

Should we set up AWS SES SMTP for this or do we have an existing solution we can use?

[jcoyne]

Should we close #258?

[peetucket]

#258 can be closed once implemented as a feedback mailto: link

Personally I don't think conversion to feedback form is necessary for this workcycle (unless @vivnwong feels more strongly about it than I do or unless there is a good reason to do it now for expediency when we have ops attention on this project).