Add documentation about sentry audit log

[AbhiPrasad]

Core or SDK?

Core Sentry product

Which part? Which one?

Audit Log

Description

There is no documentation about the sentry audit log, which makes it hard for users to understand what it can be used for (although it is referenced in other product documentation docs).

It's also hard to for users to understand what actions end up in the audit log.

Suggested Solution

Add a docs page about the audit log.

sentry.io/settings/audit-log/

Talk about what can be viewed there, and the different actions we track.