[bug 1009784] Create dev generic feedback form

[willkg]

We need a parallel form and view so that we can make changes without
affecting the existing one or the strings for it.

To access, go to /feedback/genericdev .

Quick r?

[willkg]

This is pretty unexciting. It's mostly just a copy-and-paste job.

I also added [DEV] to the page title and header so that it's clearer it's the dev one and not the regular one. When we start changing it in more obvious ways, we should remove this.

To test:

1. run tests
2. go to http://localhost:8000/feedback/ and make sure it doesn't say [DEV] in the title
3. go to http://localhost:8000/feedback/fxos and make sure it's the Firefox OS form
4. go to http://localhost:8000/feedback/genericdev and make sure it says [DEV] in the title

[rlr]

WFM r+!

[willkg]

Landed in master in: 6a78715 [bug 1009784] Create dev generic feedback form