Reduce Marketo events on PPC form.

Removes the following events from Marketo to reduce the queue and over-reporting: 

* `/event/account/create/success` (this is not necessary, the event should always be "/account/create/success" it should not be prefixed with "/event")
* `/event/-free-trial-success`
* `/event/seo-form-email-focus`
* `/event/seo-form-name-focus`
* `/event/seo-form-url-input-focus`
* `/event/seo-form-phone-number-focus`

Also removes the Munchkin `associateLead` call in oform_globals.js since the Segment `.identify` call works now that we have fixed the private key.

Once this is deployed, these are the only events that get sent out on the marketing side:

1. `/account/create/success`
2. `/event/plan/null` denotes a user signed up for an account, but is not subscribed to a plan
3. `/free-trial/success` denotes a user signed up on the ppc landing page
4. `/free-trial/` pageview
5. `/free-trial/` pageview
6. `associateLead` (create's a lead)

4 and 5 are duplicates of the same pageview event. I'm not sure why this is happening, but I see this happening elsewhere on the marketing website under certain conditions. I think this will take more investigation. It may have something to do with Segment since I don't think we are manually tracking pageviews.

There are still a ton of events that get sent out to Marketo on /edit (in the product), but we won't be able to change that anytime soon.
@dtothefp technically it doesn't have to be a string, but integration names can be invalid javascript. e.g. Google Analytics, would not work:

```js
integrations: {
  Google Analytics: false
}
```

Results in a JavaScript error. So it's always best to do a string.