Segregate centralized analytics per environment

[ilmotta]

Problem

We found in MixPanel a concerning number of events being published from builds that appear to come from non-production usage. Instead of relying on internal conventions with CCs while they develop/test in their own machines or when using PR builds, it's better to use separate MixPanel projects per environment.

Implementation

In MixPanel there are two projects we care about, production (named status-im) and test (named test.status-im).

We should inject two vars in the CI, MIXPANEL_APP_ID, MIXPANEL_TOKEN. Only release builds should use the production project, and all the rest should use the test project. The vars values are not secrets https://developer.mixpanel.com/reference/project-token, and actually the MixPanel token can be exploited, as is the case for analytics tools integrated with clients.

We could make the Status Proxy handle requests to MixPanel and that would even help with not exposing users' IP addresses directly to MixPanel if they opt-in to analytics, but this supposed improvement is outside the scope of this issue.

Acceptance Criteria

• PR builds send events to MixPanel's test project https://eu.mixpanel.com/project/3403729/view/3908497/app/home.
• Release builds send events to MixPanel's production project https://eu.mixpanel.com/project/3350627/view/3857659/app/home.