BSC audit log record must contain login

[antonkovalenko]

It was discovered that some records in blob storage controller audit log don't contain login info of a user who initiated a request.

It's important to always in every possible case to log login of a user, who initiated a request to the system that caused changes in BSC.

DoD:

1. All use-cases that cause BSC changes are listed in the comments
2. Measures to log username of a subject who caused changes are listed, some are converted to separate issues
3. IP address of YDB client is logged as well
4. All cases are covered and username could always be found in BSC audit log