Rename throttle_unauthenticated_* columns in application settings

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

• Label this issue
• Work on this issue
• Close this issue

Summary

In #335300 (closed) we're introducing a new rate limit for unauthenticated API requests, so the previous general unauthenticated rate limit now only applies to web requests.

We want to add _web_ to these columns:

• throttle_unauthenticated(_web)_enabled
• throttle_unauthenticated(_web)_period_in_seconds
• throttle_unauthenticated(_web)_requests_per_period

We can't do this yet because the V2 version of rename_column_concurrently doesn't support default values, and the old version has a bug with no-downtime deployments (see discussion at !69379 (comment 667507871),). So we decided to postpone the rename of the columns for now.

We can either reopen the existing MR !69379 (closed), or use it as reference (note that this currently still uses the V1 helper).