Adds Campaign Magic Link support

[aaronschachter]

What's this PR do?

• Adds a new DSOCampaign.magicLinkCopy property and loads from API.
• When set, our CampaignView renders the copy as a link that opens the Campaign up in a web browser, with our current user authenticated automagically 🐇 🎩 🔥
• Adds Google Analytics event tracking on tap

  How should this be reviewed?

  Local:

Run this branch on Debug. Load Animals > Space Jam (campaign id 1631) and verify:

• [x] The Magic Link renders per design and copy matches API.
• [x] Upon tapping, the Space Jam campaign is opened in web browser
  • NOTE: The Space Jam campaign will display a red warning with PHP notices that can be crossed out, and then displays a message about Global Translations are not enabled for Space Jam. That's ok for our testing purposes, the campaign is loaded.
• [x] On web, verify our current user logged in.
  • Click on the Hamburger menu to go to My Account. Verify account matches your current user in iOS app.
• [x] Back in iOS app, verify the Magic Link doesn't appear when not set, like in Animals > Justice For Elephants (campaign id 1198)

  Fabric:

Verify Animals > Bumble Bands has a Magic Link rendered per https://github.com/DoSomething/LetsDoThis-iOS/issues/1035#issuecomment-241581164

Can test the toggle with a production campaign by setting and unsetting its Magic Link Property in the Phoenix admin. To verify changes, you'll need to force quit the iOS app and reload the campaign.

Screenshot

Relevant tickets

Fixes #1035

cc @lkpttn @NearChaos

[aaronschachter]

There's some odd (or unknown to me) caching behavior going on the production Phoenix API that I didn't experience on staging.

About 30 minutes ago I set a magic_link_copy value for Bumble Bands on production to unblock testing, but I can only get a value to appear within the AFNetworking GET response by adding setting the cache=false query parameter (https://github.com/DoSomething/LetsDoThis-iOS/commit/fc84323df139e31af294a439f59e2ba07b85aa3f). I tried clearing the production Drupal cache but it didn't update it within iOS. The strange thing is that when i load the URL in browser, I do see the updated magic_link_copy... its the iOS simulator that's not seeing any updates.

Merging for now (without the cache=false hotfix) and keeping an eye on it, suspecting / hoping it's just the Varnish cache... but seems odd if it looks fine on web:

Chrome:

Xcode:

cc @weerd @katiecrane

[aaronschachter]

I've tested on Dog Days of winter also, but didn't load the Campaign Detail until I first set the copy in Phoenix admin and cleared cache. It does show up.. but still not seeing it for Bumble Bands.

[aaronschachter]

Seeing the link appear for Bumble Bands now in latest test build, removed as an item in #1049.