submission process for preinstalled apps (bug 907378)

[Bug](https://bugzilla.mozilla.org/show_bug.cgi?id=907378)

[Mock](https://bug907378.bugzilla.mozilla.org/attachment.cgi?id=799698)

**Bug Notes:**

- Need TOS copy
- Need email for Mozilla operator business contact for questions about preinstalls (currently using app reviewers email)
- Need test plan template (currently pointing at [dummy](https://github.com/ngokevin/zamboni/compare/preop-sq?expand=1#diff-66ad3743355798577f9eab7f8b91096eR156))

**Code Notes:**

- Store files on disk, not db
- File upload not via ajax since the form is only an upload input and a checkbox input.
- Included a .pdf for testing...best practice?
- Keeping track of whether a test plan template is outdated by having keeping a [datetime constant in the settings](https://github.com/ngokevin/zamboni/compare/preop-sq?expand=1#diff-513c89fb4c816bfe742638edee4a1801R1)
- No true pdf/xls validation done, just trusting the mime type with ```file.content_type```
- Test plans are saved in ```settings.ADDONS_PATH``` with a timestamp suffix, filename kept track in db

**Screenshots**

![screen shot 2013-09-30 at 1 11 42 pm](https://f.cloud.github.com/assets/674727/1240480/9bee6e14-2a0c-11e3-8f39-6ab6c44d7b0f.png)
![screen shot 2013-09-30 at 1 11 48 pm](https://f.cloud.github.com/assets/674727/1240481/9d67cb1e-2a0c-11e3-812a-0a5035d948e4.png)
![screen shot 2013-09-30 at 1 11 54 pm](https://f.cloud.github.com/assets/674727/1240482/9ea58ce6-2a0c-11e3-96ca-b6a9f9242067.png)
![screen shot 2013-09-30 at 1 12 07 pm](https://f.cloud.github.com/assets/674727/1240483/9fd5777a-2a0c-11e3-8e28-842aa1d72457.png)