Update puppet/modules/nginx/templates/mime.types

Adding missing svg mimetype
Merge branch 'dev' of github.com:mozilla/mozilla-ignite into dev
Update puppet/modules/nginx/templates/mime.types

Adding missing svg mimetype
Merge branch 'dev' of github.com:alfredo/mozilla-ignite into dev
Update puppet/modules/nginx/templates/mime.types

Adding missing svg mimetype
Merge branch 'dev' of github.com:alfredo/mozilla-ignite into dev
Add migration notification to the ``base.html`` template.

The site will be migrated and a notification is required,
the final copy is missing.

In order to trigger the notification banner a ``migration`` notice
``switch`` is required.
Add mechanics to export the existing ``app`` submissions.

The submissions are exported as JSON to be consumed
by the new ``US Ignite`` site.
Update copy and style of the migration banner.
Fix typo.
Merge pull request #152 from alfredo/dev

Introduce migration banner and tool for migrating apps content.
Merge pull request #153 from mozilla/dev

Merge dev changes to stage environment.
Merge pull request #154 from mozilla/stage

Merge stage environment to production codebase.