Analytics incorrectly capturing url data for domains other than rerun.io

[jleibs]

Our intent for the url analytics property has always been to only collect data from rerun.io.

See the comment:

    /// The URL on which the web viewer is running.
    ///
    /// We _only_ collect this on `rerun.io` domains.
    pub url: Option<String>,

This filtering did not end up getting implemented correctly and so we have leaked a small number of events containing non-rerun urls. These events can contain data such as the user internal domain-names that are less anonymized than we would like given the spirit of our policy.

At time of writing this data is made up of 475 analytics-events across 25 unique non-rerun non-localhost urls.

Proposed mitigation

Prior to 0.16 release

• Rename event url -> rerun_url to make the intent more clear.
• Fix the filtering logic to only include urls from the rerun.io domain.

After the 0.16 release

• Configure the posthog property filter to mask future incoming properties named url so that we drop data from older versions of the app.
• Manually delete the 475 historical events that contain inappropriate url data.