Contact form doesn't work on staging #310

Added html for alert placeholder.
Contact form doesn't work on staging #310

- Add html for alert
- Update ajax response to set message
- Add test coverage
Applications should be able to have multiple owners

For private client apps to be usable, more than one user should be able to use them to authenticate/authorize

TODO: delete client app when last owner is destroyed
TODO: more cleanup
Create model to manage user-application many-to-many join

Create Membership model to map users to OAuth Applications. Also include a 'member_type' field to differentiate Owners and Developers
Update benefits.gov and businessusa logos

Fixes #314 and #324
Merge pull request #327 from 18F/hotfix/partner-logos

Update benefits.gov and businessusa logos
Set up destroy hooks for Doorkeeper::Application

Trigger a destroy on the application if the last owner is being destroyed. Also want to destroy memberships when either the user or the application is destroyed, which makes things tricky.
Remove owner foreign key from oauth_applications

To support multiple owners, we use the join table (memberships), rather than a foreign key on oauth_applications
Contact form doesn't work on staging #318

Test cleanup
Merge pull request #321 from 18F/feature/many_owners

Applications should be able to have multiple owners
OK, sorry, had NR in the Gemfile too much
Client app 'developers' should be allowd to Authenticate
Merge pull request #335 from 18F/feature/many_owners

Client app 'developers' should be allowed to Authenticate
Merge pull request #334 from 18F/hotfix/less_newrelic

Remove extra newrelic from the Gemfile
Merge pull request #318 from 18F/hotfix/contact-form-alert

Contact form doesn't work on staging
Merge branch 'devel' into feature/not-me-redirect
Add at test