Add a form to submit CONSUL installations

[javierm]

Copying from consuldemocracy/consuldemocracy#2828:

Context

In an effort to sync all the CONSUL forks around the world, we've created consulproject a repo that is meant to substitute one day the current consulproject website

For now we have Github integration to see the differences between a fork and upstream.
And many other ideas are being suggested to make an awesome site of CONSUL installations around the World

What

Add a public form to submit a CONSUL installation with the following fields

• Name of fork
• Repo url
• Website url
• Contact name
• Conact Email
• Location (city/country)
• Organization type (Government, ONG, University, School, Other)
• Status (Installation in progress, In production)
• Notes

How

• Extending the current Installations model to include these columns
• Creating the corresponding views and controller actions to submit an installation
• Writing some specs to make sure everything is working nicely