Remove deprecated private DSN

[ChristophWurst]

Feature Request

Only use the "public" DSN.

From https://docs.sentry.io/error-reporting/quickstart/?platform=javascript#configure-the-sdk

As of Sentry 9, we removed the need to provide the secret key. Older versions of SDKs may still require you to provide the DSN including the secret which is now called DSN (Legacy).

⚠️ might not work for older, on-premise installations getsentry/sentry-electron#61.

[rullzer]

I'd say we just kill of the public-dsn with v5

[rullzer]

Ah wait we need some migration step indeed. Ok then lets do a DSN service that just grabs the right DSN. And then put a warning up somewhere.

[ChristophWurst]

I would do a simple migration step.

If the public dsn is set, we're done. Otherwise, the private dsn should be set (this was the requirement in the past). We pass that to Raven_Client::parseDsn(), build a new one without the password and set it as public dsn.

Then we don't need any warning. The migration should just work for all installations.