Migrate to using Microsoft ILogger abstraction

[Hawxy]

I mentioned this to Ryan as the other breaking change that'd be useful to do at the same time as the cache abstractions for pluggability.

• Eliminates the custom logging interface.
• Adjusts the log structure to use named placeholders and ensures exception stack traces get properly reported.
• Migrates the tests to use the Microsoft-supplied testing abstractions

There's an additional advantage that the logs could be migrated to use source-generated logging down the road to avoid allocations when specific log levels are disabled.

I've kept the console logger enabled out of the box as before.