Mask EUII logs

[oldalton]

Proposed changes

MSAL and broker provide logging callbacks that assist in diagnostics. By default the library will not return any messages with any user or organizational information. However, this might make diagnosing issues difficult.

The most sensitive information is EUII (things like upn, name, email etc).
This PR introduces a new logger flag and macro that allows masking only EUII, while keeping EUPI and OII intact.

When both piiEnabled is set to YES, and maskEUII is set to YES, MSAL logs will still include OII (organization identifiable information), and EUPI (end user pseudonymous identifiers), but MSAL will try to exclude and/or mask any EUII (end user identifiable information) like UPN, username, email from its logs.

This flag has no effect when piiEnabled is set to NO.
Default value is NO.

Type of change

• Feature work
• Bug fix
• Documentation
• Engineering change
• Test
• Logging/Telemetry

Risk

• High – Errors could cause MAJOR regression of many scenarios. (Example: new large features or high level infrastructure changes)
• Medium – Errors could cause regression of 1 or more scenarios. (Example: somewhat complex bug fixes, small new features)
• Small – No issues are expected. (Example: Very small bug fixes, string changes, or configuration settings changes)

Additional information

[kaisong1990]

LGTM