* Improve opt-in opt-out event tracking after going 'back' in onboarding.
* Fix 'Switched Networks' metrics event.
* Fix custom variables ids (can only use ids 1-5)
* Fix tracking of function type custom variable for metametrics in confirm-transaction-base
* Add missing metametrics events
* Add metametrics provider and util.
* Add backend api and state for participating in metametrics.
* Add frontend action for participating in metametrics.
* Add metametrics opt-in screen.
* Add metametrics events to first time flow.
* Add metametrics events for route changes
* Add metametrics events for send and confirm screens
* Add metametrics events to dropdowns, transactions, log in and out, settings, sig requests and main screen
* Ensures each log in is measured as a new visit by metametrics.
* Ensure metametrics is called with an empty string for dimensions params if specified
* Adds opt in metametrics modal after unlock for existing users
* Adds settings page toggle for opting in and out of MetaMetrics
* Switch metametrics dimensions to page level scope
* Lint, test and translation fixes for metametrics.
* Update design for metametrics opt-in screen
* Complete responsive styling of metametrics-opt-in modal
* Use new chart image on metrics opt in screens
* Incorporate the metametrics opt-in screen into the new onboarding flow
* Update e2e tests to accomodate metametrics changes
* Mock out metametrics network requests in integration tests
* Fix tx-list integration test to support metametrics provider.
* Send number of tokens and accounts data with every metametrics event.
* Update metametrics event descriptor schema and add new events.
* Fix import tos bug and send gas button bug due to metametrics changes.
* Various small fixes on the metametrics branch.
* Add origin custom variable type to metametrics.util
* Fix names of onboarding complete actions (metametrics).
* Fix names of Metrics Options actions (metametrics).
* Clean up code related to metametrics.
* Fix bad merge conflict resolution and improve promise handling in sendMetaMetrics event and confrim tx base
* Don't send a second metrics event if user has gone back during first time flow.
* Collect metametrics on going back from onboarding create/import.
* Add missing custom variable constants for metametrics
* Fix metametrics provider
* Make height of opt-in modal responsive.
* Adjust text content for opt-in modal.
* Update metametrics event names and clean up code in opt-in-modal
* Put phishing warning step next to last in onboarding flow
* Link terms of service on create and import screens of first time flow
* Add subtext to options on the onboarding select action screen.
* Fix styling of bullet points on end of onboarding screen.
* Combine phishing warning and congratulations screens.
* Fix placement of users if unlocking after an incomplete onboarding import flow.
* Fix capitalization in opt-in screen
* Fix last onboarding screen translations
* Add link to 'Learn More' on the last screen of onboarding
* Code clean up: metametrics branch
* Update e2e tests for phishing warning step removal
* e2e tests passing on metametrics branch
* Different tracking urls for metametrics on development and prod
